Office Live Workspace
Microsoft’s first try at online editing of documents, Office Live Workspace was free for all kinds of users. The service has been discontinued in January 2011 and was replaced with “Office Web Apps on SkyDrive”.
Office Web Apps on SkyDrive
Targeted towards home users and students, this free solution allows users to view and edit documents through most web browsers, share them and collaborate on Office documents with others.
Documents from SkyDrive can easily be opened in the full versions of Word, Excel and PowerPoint, if the user has them installed, but purchasing these applications is not required to use Office Web Apps on SkyDrive.
Go to Office Web Apps on SkyDrive
Office Web Apps on-premises
Business users who purchase Office 2010 through volume licensing can run Office Web Apps for their users on own servers by installing SharePoint 2010.
Learn more about deploying Office Web Apps
E-mail centric services
Windows Live Hotmail
One of the world’s most popular e-mail services for personal use, Hotmail gives users a huge inbox accessible through most web browsers and the choice of an address under one of hotmail.com or several other domains.
Go to Windows Live Hotmail
Currently in beta, Office 365 seems to be meant to replace the functionality currently offered through Office Live Small Business and Microsoft Online Services. It is going to offer hosted Exchange, SharePoint and Lync services together with licenses to run Office Professional Plus on customer workstations at different service levels priced between $2 and $27 per user and month.
Go to Office 365