Microsoft has their own on-line, cloud based education document sharing portal, based on their Office 365 service. While also free to educators, it is not as widely deployed as Google Docs.
However, things change quickly on the Internet and Office 365 is definitely worth considering, especially if you ware already comfortable with Microsoft applications.
Microsoft's introductory page on it's Office for Education offering.
Scroll down past the Get Started form to learn about their product.
Office 365 Education, their Internet based solution, is free for your entire school. For a small fee per student, you can add installed copies of Office on PC and mobile platforms, analytics tools and additional features.
This June, 2013 Infoweek article takes a look at two different school systems, and what factors went into choosing the products they did.
This September 2015 article looks at 8 key differences between Google Apps for Education and Office 365. The article is written more for tech geeks than the average educator, but brings up issues worth considering.
This look is at both on-line applications. The review highlights the underlying strengths and weaknesses of each offering.
An in depth article from Campus Technology looking at the issues that need to be considered when implementing Google Apps or Office 365 in an education setting.
Other Areas To Check Out...
• Getting Started And Happy Endings
• Glossaries for Space Adventurers and Mere Mortals
• Group Conferencing
• Image Software
• International Libraries
• Music -- Theory and Practice
• On-Line Collections - Universities and Public Institutions
• On-Line Document & Collaboration Options
• Other National Resources
• Traditional Desktop Publishing Tools