At the Times Center in New York this morning, Facebook COO Sheryl Sandberg delivered a keynote Advertising Week presentation to a packed house, titled, “Facebook: Knowing Is Better.” The big news of the day was Facebook’s partnership with Nielsen Online to better measure ads on the site.

Sandberg admitted that the company has “had some stumbles, some of our own making,” but also mentioned, “If you’re not on Facebook now, you’re not part of the conversation.” She also used the opportunity to ding The New York Times – in their own building – for a recent story, “Facebook Exodus.” “Unfortunately for the Times, it came out days before we announced our 300 million users,” she said.

Getting into the marketing opportunities on the site, Sandberg highlighted that there are more than 1.4 million active fan pages on Facebook and “three of the top 15 are brands.” Those brands are Skittles, Coke and Starbucks. In terms of Starbucks, “they communicate with their users and customers the core attributes of their brand,” she said. “Howard Shultz, the CEO, posts as himself and people respond by the thousand. This doesn’t build people’s love for coffee, it builds people’s love for Starbucks.”