See also "Social networking Sites" in Webopedia's Quick Reference section.
Also see "The Differences Between LinkedIn and Facebook" in in Webopedia's Did You Know? section.

Webopedia's "Did You Know...?" Section
Use this Webopedia knowledge section for an in-depth overview of specific technologies and occurrences in the areas of Computer Science, The Internet, and Computer Hardware and Software.

Webopedia's Quick Reference Section
Use this Webopedia reference section for information on common Internet and computer facts and occurrences.