(1) MySpace

Launched: July 2003
Founded by: Tom Anderson and Chris DeWolfe
Type: Social Network
Targeted Audience: 16 - 24 (teens, young adults)
Approximate Users: 150 million (100 million as of August 2006; growing at around 200,000 registrations per day)
Approximate Pageviews: 40 billion per month (as of March 2007)
Acquisition/Valuation: Bought by Rupert Murdoch’s Fox Interactive Media in July 2005 for $580 million

(2) YouTube

Launched: February 2005
Founded by: Chad Hurley, Steve Chen, and Jawed Karim
Type: Video Sharing
Targeted Audience: 16 - 40 (teens, adults)
Approximate Users: Unknown
Approximate Pageviews: 4 billion per month (as of July 2006, serving 100 million videos per day)
Acquisition/Valuation: Bought by Google in October 2006 for $1.6 billion

(3) Facebook

Launched: February 2004
Founded by: Mark Zuckerberg
Type: Social Network
Targeted Audience: 20 - 25 (college students), this is changing since they have opened up
Approximate Users: 18 million (as of February 2007)
Approximate Pageviews: 22 billion per month (as of December 2006)
Acquisition/Valuation: Rejected $1 billion offer from Yahoo! in September 2006, asking for $2 billion

(4) Wikipedia

Launched: January 2001
Founded by: Jimmy Wales and Larry Sanger
Type: Wiki-based Encyclopedia
Targeted Audience: 10 - 80 (general)
Approximate Users: 50,000 active users (as of January 2006)
Approximate Pageviews: 6 billion per month (as of February 2007)
Acquisition/Valuation: Non-profit, has raised over $3 million in donations

(5) Bebo

Launched: January 2005
Founded by: Michael Birch and Xochi Birch
Type: Social Network
Targeted Audience: 16 - 24 (teens, young adults)
Approximate Users: 24 million (as of May 2006)
Approximate Pageviews: 4 billion per month (as of October 2006)
Acquisition/Valuation: Rejected $500 million offer from British Telecom Group, asking for $1 billion

(6) Digg

Launched: November 2004
Founded by: Kevin Rose
Type: Social Content Bookmarking/Voting
Targeted Audience: 16 - 30 (teens, adults; technology-savvy)
Approximate Users: 1 million
Approximate Pageviews: 118 million per month (as of 2006)
Acquisition/Valuation: Rumored to have been in negotiations with Fox Interactive/Newscorp, asking for $150 million

(7) Flickr

Launched: February 2004
Founded by: Ludicorp
Type: Photo Sharing
Targeted Audience: 16 - 80 (general)
Approximate Users: 1.5 million (as of November 2005)
Approximate Pageviews: Unknown
Acquisition/Valuation: Bought by Yahoo! in March 2005 for an undisclosed price estimated in the lower tens of millions.