Social Documents are suites of web-based programs and file storage that run in a web browser, offering a single point of entry for communication and productivity tools.

You grant others access, which facilitates collaboration, peer review of academic materials, and the collective generation of knowledge.

Common elements are word processing, spreadsheets, and presentation software.

Blogs and wikis are other kinds of social document creation that you are familiar with.

Blogs:

• A blog—shorthand for "Web log"—is an online collection of personal commentary and links.
• Anyone can create a blog for free.
• Authority and content are not restricted.
• Twitter is a microblog and social network.
• Applications: Blogger, Movable Type, WordPress

Wikis:

• Wikis are Web pages that can be viewed and modified by anyone with a Web browser and Internet access.
• They support asynchronous communication and group collaboration online.
• Applications: MediaWiki
   

Applications and Websites that allow individuals to create profiles or web pages that include almost anything they want to post and dynamically links their information to others.

Usually different applications work in different ways but the main concept is the same.