Yahoo! Mail
Yahoo! made a deal with the online communications company Four11 for co-branded white pages. Marvin Gavin, who worked at Four11 as the Director of International Business Development, said "We always had a bias about being acquired by Yahoo. They were more entrepreneurial than Microsoft. We had a great cultural fit – it made a lot of sense." In the end, Yahoo! acquired Four11 for $96 million. The purpose behind acquiring Four11 was the company's RocketMail webmail service, which launched in 1997. Yahoo! announced the acquisition on October 8, 1997, close to the time that Yahoo! Mail was launched. Yahoo! chose acquisition rather than internal platform development, because, as Healy said, "Hotmail was growing at thousands and thousands users per week. We did an analysis. For us to build, it would have taken four to six months, and by then, so many users would have taken an email account. The speed of the market was critical."
Hightail
Throughout 2008, YouSendIt added plugins that allowed files to be sent through YouSendIt from within applications like Final Cut Pro, Microsoft Outlook, and Adobe Acrobat. In May of that year, a new release of Yahoo! Mail included YouSendIt built-in, which added a million YouSendIt users over the following two months. In July, YouSendIt's online folder management system and digital signing features were introduced in order to compete with Dropbox. The following month, YouSendIt added applications for Mac and PC desktops, as well as iOS and Android devices.