Gmail

GmailShort for Google mail, Gmail is a free service provided by Google that enables users to send and receive e-mail over the Internet. Gmail was initially thought of as a joke because it was announced April 1st, 2004. What initially made Gmail unique and still unique from other similar services is the ability to store several gigs of e-mail meaning almost all users never have to worry about e-mails being prematurely deleted or the inability to receive e-mails because they have exceeded their quota and that it allows users to have a Gmail account for up to nine months of inactive use, where similar services require users to log in at least once every 30 days.

Also see: E-mail, ESP, Google, Hotmail