Windows Live Hotmail, formerly known as MSN Hotmail and commonly referred to simply as Hotmail, is a free web-based email service operated by Microsoft as part of its Windows Live group. It was founded by Sabeer Bhatia and Jack Smith and launched in July 1996 as 'HoTMaiL'. It was the first web-based email service. Its original name and capitalization refers to HTML, the encoding language used by the World Wide Web. It was also one of the first free email providers. It was purchased from the original creators by an Estonian investor Steve Jurvetson, who continued developing it. Hotmail was acquired by Microsoft in 1997 for an estimated $400 million, and shortly after it was rebranded as 'MSN Hotmail'. The current version, "Windows Live Hotmail", was officially announced in 2005 and released worldwide in 2007.
Windows Live Hotmail features unlimited storage, security measures for which patents have been filed, Ajax technology, and integration with Windows Live Messenger, Hotmail Calendar, SkyDrive and Contacts. According to comScore (August 2010) Windows Live Hotmail is the world's largest web-based email service with nearly 364 million users. Second and third are Yahoo! Mail, 280 million and Gmail, 191 million. It is available in 36 different languages.