• by Mark Walsh  @markfwal, November 12, 2007

When Facebook launched its new ad platform in New York last week, it wasn't just a one-day splash for the Silicon Valley-based social networking site. The company has been quietly operating out of a new ad sales office in midtown Manhattan for the last few months.

Facebook currently has about 20 employees in New York led by Tom Arrix, vice president of East sales. A company spokesman says Facebook doesn't have specific hiring goals for the office, but is growing rapidly. With its new "social advertising" platform in place, Facebook is seeking closer ties to Madison Avenue through the New York branch.

Facebook follows in the steps of Internet rivals such as Yahoo and Google, which have each established a large presence in New York to help cultivate closer relations with the advertising community.

Major marketers including Blockbuster, Coca-Cola and Sony have already signed on to Facebook's new ad strategy, which lets members register as "fans" of particular brands, among other things.

Facebook hasn't gotten the warmest welcome in New York, legally speaking. Last month, the company agreed to settle a probe by New York State Attorney General Andrew Cuomo into complaints relating to harassment and pornography on the site. Facebook is adopting additional safety procedures to protect minors and others on its network.

And last week, a law professor raised questions about whether Facebook's new ad plan would be legal in New York under a 104-year-old state law that bars advertisers from using photos, or other likenesses of people without their written permission.

So where exactly are Facebook's New York digs? A recent post on the Silicon Alley Insider blog identified 551 Fifth Avenue as the location of Facebook's New York outpost, where it rents 5,350 square feet at $65 per square-foot. The Facebook spokesman wouldn't confirm those details, but says the office is located on Fifth Avenue.

In contrast to its under-the-radar New York office, Facebook hosted an upscale affair at a Manhattan loft space usually reserved for weddings and bar mitzvahs to debut its new ad platform. With top media and ad bosses on hand, it was something of a coming-out party for the company and its 23-year-old chief executive Mark Zuckerberg, at least until (and if) Facebook files for an IPO.