Yahoo! Mail (shortened as Y! Mail) is a web-based email service created by Yahoo! and is also owned by them. It was inaugurated in 1997. Yahoo! Mail serves over 280 million users as of 2009. It is currently the largest web-based email service, after its competitor Windows Live Hotmail.
Currently, Yahoo! offers two versions of Yahoo! Mail: an Outlook-like Ajax interface powered by Yahoo!'s Zimbra introduced in 2007, as well as the traditional static-web-page "Yahoo! Mail Classic," which continues the availability of the simpler 1997-2006 interface for the brand's considerable installed base of users. In early 2008, Yahoo! started offering unlimited mail storage even to its non-paying users, in response to heated competition in the free-webmail market segment.
In June 27, 2009, Yahoo! Messenger was integrated with Yahoo! Mail Beta. This means that Messenger and Mail are together at one place. You can connect instantly with friends that are online, switch seamlessly between email and chat, and no download or setup required. This new feature is not available for Mail Classic.

History
The history of Yahoo! Mail began with JoJo Healy, Yahoo!'s resident investment banker since November 1996, who has dealt with every Yahoo! acquisition since it was created. "No one knows your business like your employees," he said. According to him, the main question was always to consider whether to "build, buy or rent." The answer really depended on the growth of competitors and the current position of the company. The main reason to buy things was to gain speed to market.
The growth in the number of Internet users eventually boosted the e-mail technology, but also created a very competitive environment where the winner was the first company to launch a successful e-mail service and attract potential users. E-mail became one of the most important features of a Web company as it would mean regular visits from e-mail users to the website.
When Hotmail and Mirabilis (the creator of the instant messenger ICQ) were looking to be bought, Yahoo! was the first company to which both made offers. Yahoo!, however, passed on both companies as they were too expensive for Yahoo! at that time. In the end, Microsoft ended up buying Hotmail for $400 million and AOL bought Mirabilis for $288 million.
Later there was also to be another battle to acquire the online communications company Four11. Yahoo! made a deal with the company for co-branded white pages. Marvin Gavin, who worked at Four11 as director of international business development said, "We always had a bias about being acquired by Yahoo! They were more entrepreneurial than Microsoft. We had a great cultural fit – it made a lot of sense." The real point in acquiring Four11 was that in March 1997, the company had launched Rocketmail, a webmail system that could be offered to users. In the end, Yahoo! concluded a deal with Four11 for $96 million. Yahoo! announced the acquisition on October 8, 1997, very close to the time that Yahoo! Mail was launched. Yahoo! Mail resulted from an acquisition rather than internal platform development because, as Healy said, "Hotmail was growing at thousands and thousands users per week. We did an analysis. For us to build, it would have taken four to six months, and by then, so many users would have taken an e-mail account. The speed of the market was critical."
The transition to Yahoo! Mail was not easy for many Rocketmail users at first. Yahoo! released various help pages to try and help these users. Soon after, on March 21, 2002, Yahoo! cut free software client access and introduced the $29.99 per year Mail Forwarding Service. Mary Osako, a Yahoo! Spokeswoman, told CNET, "For-pay services on Yahoo!, originally launched in February 1999, have experienced great acceptance from our base of active registered users, and we expect this adoption to continue to grow."
During the summer of 2002, the Yahoo! network was gradually redesigned. On July 2, Yahoo.com was redesigned and it was announced that other services like Yahoo! Mail would enter the same process. Along with this new design, new features were to be implemented, including new navigation tools, such as drop-down menus in DHTML and different category tabs, and a new user-customizable color scheme.
In November of the same year, Yahoo! launched another paid service: Yahoo! Mail Plus.[9] Yahoo! Mail Plus offered a number of new features, including:
25 megabytes of e-mail storage
10 megabyte message size limit
Ability to send up to 10 attachments per e-mail
POP Access and Forwarding
Archiving of e-mail messages to a hard drive for offline access
Ability to send messages from Yahoo! Mail using other e-mail domains
200 blocked addresses and 50 filters to help screen unsolicited e-mails
No promotional taglines in messages
No account expiration.
The launch of Yahoo! Mail Plus is part of Yahoo!'s strategic initiative to offer premium services that deliver innovative, reliable and relevant services to consumers", said Geoff Ralston, senior vice president, Yahoo! Network Services, and creator of the original Yahoo! Mail technology in 1997. "In just five years, Yahoo! Mail has grown from one million to tens of millions of users, illustrating how consumers have made e-mail an essential part of their daily lives. Through Yahoo! Mail Plus, Yahoo! continues to demonstrate leadership and innovation by offering consumers the industry's most complete and powerful e-mail solution.
On April 1, 2004, Google announced a free webmail with 1 gigabyte of storage. Though Gmail, Google's e-mail service, offered a large amount of storage, its invitation-only accounts kept the other webmail services at the forefront. Most of the major webmail providers like Yahoo! Mail, Hotmail, and AOL followed Google's lead and increased their mailbox storage considerably. Yahoo! was the first provider to announce 100 MB of storage for basic accounts and 2 GB of storage for premium users. Determined not to lose customers, Yahoo! Mail then countered Hotmail and Google by increasing the storage quota of its free email accounts to 1 GB, and eventually removing a storage limit altogether and allowing unlimited storage.
On July 9, 2004, Yahoo! acquired Oddpost, a strong webmail offering that simulated a desktop email client like Microsoft Outlook. Oddpost had new innovative features such as drag-and-drop support, right-click menus, RSS feeds, and a preview pane, but it also had incredible speed, using e-mail caching to shorten response time, and many of these features were incorporated into an updated Yahoo! Mail service.
On August 30, 2007, Walter Mossberg wrote in the Wall Street Journal that Yahoo! will be releasing the new version over the next few weeks.

New Yahoo! Mail
The New Yahoo! Mail has a revised interface which contains mostly Ajax (JavaScript and XML). It is very similar to a heavy mail client like Outlook (Drag and drop capabilities, Mail search, tabs). The new Yahoo! Mail comes with an integrated Messenger; as a result, users are able to chat with Yahoo! Messenger and Windows Live Messenger contacts while reading their email.
As of August 26, 2007, the new Yahoo! Mail came out of Beta period. The development of what has now become the new interface, started since July 2004, although it is possible other prototypes were in development before then. It is currently compatible with Internet Explorer 7, Firefox and Safari as well as Camino and other Gecko based browsers. (As part of Yahoo!'s plan to eventually upgrade all of their sites to be compatible with Firefox). Although it is usable under Opera, there are slight visual problems regarding the layout.[citation needed]
In September 2005 Yahoo! began beta testing a significantly enhanced version of their e-mail service, based on Ajax scripting acquired from Oddpost, along with new philosophical approaches to email, including the Oddpost design philosophy (which Google made heavy use of in Gmail):
Given that the All-New Yahoo! Mail is based on Oddpost, it features the same underlying code base, including the implementation of this design concept to minimize the amount of data sent during an email session by creating a JavaScript UI engine on the client side and sending "Datapacks" instead of reloading the whole interface on every click like a traditional webmail service (e.g. traditional Yahoo! Mail). This makes the service much faster than its counterparts.
However, unlike Oddpost, All-New Yahoo! Mail runs on a variety of OSes and browsers, and runs perfectly under Internet Explorer 7 and Firefox. On February 13, 2008, Yahoo! announced on the Yahoo! Mail blog that it would begin supporting version 3 of the Mac OS X default browser Safari, as well as the Mac versions of Firefox.
The look and feel of the new version is designed to mimic a desktop e-mail client, and it offers unlimited storage space, tabbed emails, RSS feeds, drag-and-drop capabilities, advanced keyboard shortcuts, advanced search, integration with Yahoo! Calendar and Messenger, Domain Keys, address auto-complete and more.
The All-New Yahoo! Mail also has a mascot called Liam, who is basically a little boy, who is shown in the "Help" panel as well as in the loading screen. Liam is "mail" spelled backward.

Introduction
Wide-scale beta release of the new version was introduced in late 2006. In November 2006, the Mail Beta team announced plans of integrating Yahoo! Messenger functionality with the Mail Beta interface. This service was deployed in March, 2007.
Public and critical reaction to the new product has been positive,although a number of users have encountered speed issues, which can render the client very difficult to use, especially on older hardware. Each update to the Beta has included significant speed improvements, and the Mail Beta team is still focused on improving speed issues. For example, the earlier versions of Mail Beta featured a loading screen every time you access mail. However, with various updates Mail Beta now appears immediately (no loading screen).
On August 26, 2007, Yahoo! Mail left beta and now the two versions which exist are known as Yahoo! Mail (the default interface) and Yahoo! Mail Classic (an updated version of the current interface). The announcement was made on the Yahoo! Mail blog by John Kremer, Vice President, Yahoo! Mail and the major improvements relate to intelligent shortcuts, SMS Messaging, and improved search.
The final version was released on October 9, 2007.

Features
Some of the new or improved features included in the New Yahoo! Mail are:
Yahoo! Calendar integration
Yahoo! Messenger integration
Windows Live Messenger integration
SMS Messaging in certain countries
Keyboard shortcuts
Unlimited storage
Improved search facilities
Applications(Piknic, Flickr, Wordpress and more)
In addition, an Easter egg was added called a Subject-O-Matique. This hidden feature displays a random message in the subject line when the subject button is clicked. The messages range from cultural references ("I AM the walrus") to sarcastic ("If you don't tell lies, at least you don't have to remember what you have said.") to unusual and outlandish ("the art of driving a giant, nuclear powered duck").
On December 15, 2008, Yahoo! Mail introduced features to make it more social.

Yahoo! Mail Classic

Mail Classic is, since the launch of the new Yahoo! Mail, an optional secondary User Interface for Yahoo! Mail. Although the AJAX interface is the default one, Classic is available for users who prefer to use the legacy style interface. In March 2009, Yahoo! Mail Classic integrated Yahoo! Messenger is its interface so people can chat and email at the same time.

Yahoo! Mail has the following features:

Free version
Unlimited Mail Storage.
10 MB attachments (20 MB for the Plus version)
100 filters to automatically sort incoming messages (200 filters for the Plus version)
Protection against spam and viruses. (See: DomainKeys)
Advertising is displayed on the screen while working with the e-mail account, but text ads are not within the emails themselves, and they are no longer added to the footer of outgoing messages.
POP3 support, Mail Forwarding facility, and SMTP support in some countries (but not in the US).
Accounts not logged into for four months get deactivated (The account can be retrieved but all stored data, such as emails, are lost).
Early in 2006, Yahoo! Mail introduced aliases to its repertoire of features. Users could now add a (single) alias username containing a dot character for a pre-existing account.
The Chinese version of Yahoo! Mail offers 3.5 GB quota and 20 MB attachments. [3]
Some users get features added if they are long time users.
Latest beta of Yahoo! Zimbra desktop allows for all Yahoo! users to use the software
Users can get around the Web browser access restriction by using software that simulates a POP3 server to which the e-mail application connects. YPOPs! and FreePOPs are examples of free software applications that allow e-mail clients access to webmail (including Yahoo! Mail) services through POP3.
Another way of getting POP3 access without signing up for the paid mail plans is signing up for Yahoo! Delivers, a service which sends the user promotional email messages. According to the Yahoo! Mail help pages,"Yahoo! offers POP access to Yahoo! Mail as a free feature exclusively for Yahoo! Delivers members".

Business
Yahoo! Business E-mail is a combination of all of their e-mail services with 10 distinct accounts each with the same features of the plus version and personalized domain name and e-mail address. Accounts can be managed by an administrator. There is $25 set-up fee and $9.99 monthly fee to use this service. Yahoo! is still working out how to allow their business mail clients to access their email accounts from certain mobile smart phones and PDAs. According to Yahoo!'s website, for now, you can access your Business Email only from a BlackBerry. Yahoo! says it plans to make business email compatible with more devices in the future. Yahoo!'s Business mail is also not compatible with the latest releases of Leopard/Safari. It is compatible with the latest releases of Safari - but only when running on Tiger.
Unlimited Mail Storage
10 E-mail quota.
Additionally, a user can pay $35 per year to have up to five custom e-mail addresses and a domain name.
Yahoo! Mail underlines addresses and phone numbers in emails and allows the user to add them to the address book.

Ymail and Rocketmail
Yahoo! Mail Vice President John Kremer on June 19, 2008 announced the tripling of the size of its free online e-mail service with the launching of 2 domains as options for its 266 million users of "@yahoo.com" addresses: the new, simpler e-mail addresses ending in ymail.com and rocketmail.com. Rocketmail has a "hip retro feel" since it is a resurrected email address of a 1997 Yahoo service.[20] E-mail under the ymail and rocketmail domains will offer all the same features as the Yahoo domain, with an unlimited amount of storage capacity, with ability to instant message from within their e-mail inbox and spam and virus protection.