• by Gavin O'Malley  @mp_gavin, March 4, 2010

Another day, another executive departure at AOL. Mike Rich, until now SVP of AOL Entertainment -- including AOL Music, Moviefone, and AOL Television -- is out as of April 1. Rich spent nine years at AOL.

The move comes on the heels of David Eun coming on as president of AOL Media and Studios, which resulted in the departure of Bill Wilson -- who himself spent nine years as president of AOL Media. "Mike ... has decided the time is right to explore new challenges," Eun said in a note to employees on Thursday morning.

Meanwhile, David Mason, co-founder of the recently acquired StudioNow, has been promoted to SVP of the AOL Content Platform, while Jeff Reynar will now lead the engineering efforts for the Content Platform, which encompasses StudioNow and Seed.com.

At the end of January, AOL announced a deal to acquire StudioNow, an online platform for creating and distributing video programming, along with plans to integrate the platform into its recently launched content management system Seed.com.

Reynar, who joined AOL in late January, has until now been building out and managing AOL's New York Technology Center, while focusing on innovation for AOL's content business. Perhaps not surprisingly, Reynar formerly worked for Google as an engineering manager.

Since March of last year, when Tim Armstrong left Google for AOL, a number of Google employees have followed his lead. Last April, Jeff Levick -- Google's then VP of industry development and marketing -- said he was jumping ship to serve as head of AOL's advertising business Platform-A.

Last September, meanwhile, AOL brought on ex-Google exec Shashi Seth as SVP of global advertising products. When Seth left Google, he was head of monetization for YouTube.

Eun himself joined AOL from Google, where as VP of Strategic Partnerships he was responsible for managing global content partnerships with Google and YouTube.

As AOL's chief content executive, Eun is now responsible for the company's more than 80 content sites and its new SEED.com publishing platform, as well as the newly acquired StudioNow video platform and AOL's NYC and LA studios.

Until 2006, Eun helped to oversee AOL as VP of operations for the Media & Communications Group at Time Warner. In that role, he helped provide operational oversight and develop new businesses -- particularly in digital distribution and broadband content and services -- for the company's AOL, Time Warner Cable and Time divisions.