Following Facebook’s announcement last week that it reached 300 million monthly active users and was “free cash flow positive,” the company has been making a concerted effort to woo the advertising industry at Ad Week in New York. Most prominently, it has announced a deal with audience research firm Nielsen this morning, where the firm will gather ad-effectiveness data from within Facebook to share with agencies and advertisers.

Nielsen will begin placing specially-designed polls within right-hand window on the homepage where “sponsored” advertising posts normally appear. More, from the companies:

Nielsen BrandLift measures aided awareness, ad recall, message association, brand favorability and purchase consideration via a set of short, specially designed one or two question surveys. The surveys collect the information marketers need as a seamless part of the Facebook user experience.

Working directly with Facebook’s advertising clients, Nielsen will conduct hundreds of Nielsen BrandLift tests over the coming months. The frequency of the surveys will be carefully controlled to limit any one user from being asked to participate too often. No personally identifiable information will be collected as part of this program.

Company chief operating officer Sheryl Sandberg talked about the deal, a multi-year strategic alliance, in more detail today at Ad Week, together with representatives from Nielsen as well as advertiser Sony. She gave the example of Proctor & Gamble’s women-focused Secret deodorant’s Facebook page. In a test run, it gained 220,00 fans in five days (apparently through advertising) and then used BrandLift to track the results. The campaign, including the page and the ads, drove 11 percent in purchase intent among the general population, and 33 percent among women between 13 and 18 years old.

Facebook seems to have already convinced many advertisers that it is a good place to spend money. For example, Nielsen said today that Facebook had 14.7 percent share of display ad views in the US for August, 2009, up from 1.8 percent in January. This echos comScore data showing Facebook and MySpace together comprised more than 20 percent of US display ads in June. Anecdotally, ad industry insiders see “massive budgeting” being done for Facebook now, along with other social media sites.

This success further explains Facebook’s continued focus on advertising versus other forms of making money, such as a payments system. It has grown its revenues this past year primarily, from our understanding, through a combination of display ads for large brands and self-serve ads for everybody else. The company is on track to make more than $550 million by the end of the year, sources have recently told us.

Facebook is meanwhile continuing to flesh out its advertising products. For example, it recently introduced a way for a brand to include a direct-response form as part of an ad, which a few companies have been using to let users sign up to receive free samples. We’ve covered how Chik-Fil-A and Texas Pete Hot Sauce have used this feature to help attract more users to their pages. Today, Sandberg said that Texas Pete has managed to give away 5,000 hot sauce samples in just two days, something it has not been able to do so easily before. We’re also seeing this unit, which Sandberg called the “engagement sample” unit, in other ads now. See the screenshot above for Bear Naked granola bars.

BrandLift will start becoming available for advertisers this week.