Andreessen Horowitz celebrates its first birthday with a number of new hires, including its third general partner - John O'Farrell - who joins founding general partners Marc Andreessen and Ben Horowitz. O'Farrell was most recently a vice president at Silver Spring Networks. We covered the launch of Andreessen Horowitz a year ago here. The company has also recently hired two partners - Margit Wennmachers to run marketing and Jeff Stump to help portfolio companies recruit executive talent.