(Google MAIL) Google's free Web-based e-mail service, which is supported by text advertising similar to Google's Web search. Launched in beta in 2004, Gmail offers 2.5GB of mailbox storage, allowing users to keep their mail on Google servers indefinitely for future reference. Gmail provides sophisticated searching of message content and keeps message threads for easy review. In 2006, Gmail chat integrated instant messaging with the e-mail, also taking advantage of the same save and search features. See Google.