245 Facebook, Inc. Palo Alto, CA

138 Twitter San Francisco, CA

18 comScore Inc. SCOR 12.77 (-1.47%)

11 Zynga San Francisco, CA

10 Activision Blizzard, Inc. ATVI 10.16 (-0.49%)

10 Foursquare

6 Union Square Ventures New York, NY

5 Boxee

5 Tumblr New York, NY

4 Etsy Brooklyn, NY

3 AMEE San Francisco, CA

3 Outside.in Brooklyn, NY

1 Disqus San Francisco, CA

1 Targetspot New York, NY

Alacra, Inc. New York, NY

Bug Labs

Clickable

Covestor New York, NY

Indeed

InfoNgen New York, NY

Meetup.com New York, NY

Oddcast New York, NY

Return Path, Inc. New York New York, NY

Simulmedia New York, NY

Tracked.com New York, NY

Wesabe San Francisco, CA

Zemanta

heyZap

iBiquity Digital Corporation Columbia, MD

3 Evan Williams Twitter

2 Reid Hoffman LinkedIn Corporation

1 Albert Wenger Union Square Ventures

1 Dennis Crowley Foursquare

1 Jack Dorsey Square, Inc.

1 Marc L Andreessen Ning, Inc.

1 Mark Pincus Zynga

Bijan Sabet Spark Capital

Brad Burnham Union Square Ventures

Brad Feld Foundry Group LLC

Daniel Ha Disqus

Dave Morgan Simulmedia

David Goodman CBS Radio Inc.

David Karp Tumblr

David S. Kidder Clickable

Dick Costolo Twitter

Gian M Fulgoni comScore Inc.

Howard Lindzon StockTwits

Isaak Karaev InfoNgen

Magid M Abraham comScore Inc.

Mark Josephson Outside.in

Matt Blumberg Return Path, Inc. New York

Michael Yavonditte Tracked.com

Robert J. Struble iBiquity Digital Corporation

Robert Kalin Etsy

Scott Heiferman Meetup.com

Steven Goldstein Alacra, Inc.

Steven Johnson Outside.in

Zach Klein Boxee