RocketMail was a free web-based email service established in the 1990s that was bought by Yahoo! in 1997 for $92 million in stock. RocketMail was an early competitor of Hotmail and was created by the Four11 Corporation.
After being acquired by Yahoo in 1997, existing RocketMail addresses remained valid, but users were not able to create new accounts with this domain, according to CNET. In June 2008, Yahoo! changed this policy to allow new RocketMail addresses to be created. At the time of the purchase, email addresses were usually only offered by Internet Service Providers (ISPs) and not through web-based providers.