Sounds like Apple is doubling down on its somewhat floundering iAd unit, which sells mobile advertising in iPhone apps. Some have speculated that Apple is only half-heartedly pursuing mobile ads, a field dominated by Google. But buried in this New York Times article about real estate space was this nugget:
Apple Inc. recently expanded iAd, its mobile advertising division, in the Flatiron district. The company had been operating on a month-to-month basis at 100-104 Fifth Avenue since January and last month signed a deal to increase its space to 45,000 square feet from 10,000, in a building also occupied by online companies like Yelp and Net-a-Porter.
-New York Times, September 28, 2011