Microsoft has also been busy announcing customer wins for Office 365 for Education recently, including a deal with the Catholic International Education Office that involves 4.5 million Catholic school students.

Google Apps for Education is being used by more than 16 million students and teachers, while Office 365 for Education and its predecessor Live@Edu has more than 22 million end users, according the companies. Apps for Education is free, while Office 365 for Education has a free version, as well as fee-based versions.

Both companies are devoting a lot of effort to the education market, where they can get in front of K-12 and college students and in theory gain a "mindshare" advantage with these future professionals.

"Dominating the edu sector is desirable for vendors because it exposes the next generation workforce to their tools, allows vendors to try out new code and concepts at very large scale before bringing them to the enterprise, and eventually allows vendors to monetize a valuable demographic as the students become alumni," said Gartner analyst Matthew Cain via e-mail.

Rebecca Wettemann, a Nucleus Research analyst, said that usability and adoption are key for the broad success of personal productivity applications like messaging and collaboration, and that users are most comfortable with applications they know.