Forget AdWords. You may get the most bang for your advertising buck on Facebook, not Google, according to a recent study.

Earlier this month the social networking site topped Google to win the title of most visited site in the U.S.  Yes, that was just one week in March (for the record, the second week). But now the social networking site has added another medal to its haul: Its news readers are more loyal than those of Google News, says research firm Hitwise.

As many as 78 percent of users returned to Facebook to access more news stories, compared with 67 percent of Google News users, according to Hitwise. Plus, 77 percent of Facebook users clicked back to the site to broadcast online news portals there, compared with 64 percent of Google News users returning for the same. The results are based on the click stream data for the week ending March 6 for the five top news media sites. (Something else to consider: Facebook is trending way up, traffic-wise. It's up a whopping 185 percent over this time last year. Google is up 9 percent – suggesting it may take second place more often in the future.)

Heather Hopkins, a senior market analyst for Hitwise, explained in a blog post why she chose to focus on loyalty: 'A few weeks ago when I posted my blog entry about Facebook being the largest news reader, I received a few comments and e-mails noting that visitors aren't as valuable if they don't come back. Advertisers and retailers need some assurance that visitors will return again and again.'

Users of Facebook clearly do come back. (After all, they've got a network of friends that repeatedly yanks them back.) Plus, they share a gold mine of marketing data, and, of course, organize those networks of friends.
Google can target ads based on keywords and personal search history, but Facebook's ads in the margins – for which there's no minimum budget – are ultra-refined, zeroing in on users based on age, geography, interests, education level, connections and a range of other data.

"Advertisers looking to target a specific audience can't do much better than Facebook," observed

Major brands already are shifting their online ad dollars from Google to Facebook – the latter of which is expected to rake in $2 billion in global advertising next year, said Ciaran Norris, Mindshare's global head of social media.

"There hasn't really been a global social network until now and the rise of Facebook has meant that now you have a platform which allows you to run campaigns that will reach users in multiple regions," Norris told Sydney's Ad:Tech conference last week. "It costs less than to build a funky microsite, and Facebook is potentially where your audience already is."

Of course, you can have your ad displayed to only the most carefully chosen audience – but can you make them read it? Here's a tip from one small business that's successfully raised its click-through rate: Humor helps. (For more on that, click here.)