Facebook has entered into a multiyear partnership with Nielsen to allow better measurement of the effectiveness of advertising on the widely popular social networking site, announced Facebook COO Sheryl Sandberg Tuesday during a talk at Advertising Week in New York City.

The first offspring of the Facebook-Nielsen alliance will be a product called Nielsen BrandLift, which will debut in the US with test partners this week and roll out to all Facebook advertisers in the coming months. BrandLift will use short opt-in polls on Facebook’s homepage to measure consumer attitudes and purchase intent in relation to display advertising that has appeared on the site, according to a Nielsen press release about the new partnership. Sandberg said BrandLift will measure audience response to a specific ad and deliver that information to the advertiser in just a few days.

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 controlled to limit any one user from being asked to participate too often, and no personally identifiable information will be collected as part of this program.

BusinessWeek's David Kiley reports that while Nielsen will design and execute the studies, Facebook will collect the data and handle consumer privacy issues.

The deal aims to reassure leery advertisers about Facebook's viability as a marketing platform. "You want measurement, measurement you can rely on, measurement that you believe is valid," Sandberg said to her audience Tuesday, reports CNET's Caroline McCarthy. Sandberg said that advertisers' hunger for measurability is what drove Facebook to approach Nielsen, according to McCarthy.

Expected to generate $500 million in revenue this year, Facebook has been testing different ad formats and programs, points out Forbes writer Helen Coster, which include:

• "Engagement sampling ads" that allow users to receive product samples in the mail if they provide marketers with their home addresses (currently being tested and expected soon to launch).
• "Engagement ads," launched last November, that let users interact with ads without leaving the site and provides details of these interactions on users' news feeds.
• Facebook Connect, introduced in December, which encourages users to voluntarily provide profile information to advertisers.

Facebook has good reason to woo advertisers aggressively, as advertising on major social networks and blogs grew 119% from August 2008 to August 2009, from approximately $49 million to about $108 million, according to Nielsen's press release, which also provided the following data points:

• The share of estimated ad spend on the top social network and blogging sites has grown from a 7% share of total online ad spend in August 2008 to a 15% share in August 2009.
• Facebook has seen significant growth as an important website for advertising with a 14.7% share of display ad views in the US in August 2009, up from 1.8% in January 2009.
• Time spent on network and blogging sites accounted for 17% of all time spent on the Internet in August 2009, nearly triple the percentage of time spent on the sector a year ago.
• In August 2009, Facebook had the 4th-largest unique audience in the US among all web brands, with 103,886,000 users.
• In August 2009, the average user spent more time on Facebook than on any other major website; average time spent on Facebook was 5 hours 46 minutes 4 seconds.