Short 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 helps make Gmail unique is the ability to store several gigabytes of e-mail data, which means most users don't have to worry about not getting e-mail due to exceeding their available storage. Another defining trait of the Gmail service is that it allows users to be inactive for up to nine months. Many similar services require a login at least once every 30 days to keep an account active. Finally, Gmail has one of the best, if not the best, spam detection capabilities available, which means almost all spam is filtered into the trash, so you don't have to read it.