Michael Dolan, chief financial officer at Viacom, said six weeks ago at The Deal's Convergence 2.0 conference in New York, that his top advertising sales executive doubted the company's traditional advertisers would want to advertise on any social networking site the company bought.

Either that top ad exec has been banished or Viacom has changed its stance. It may have realized since then that its strategy shouldn't be guided by what its ad sales team can sell, but by the new places advertisers must go to reach consumers.

One of those new places is MySpace, which announced a three year advertising agreement with Google today. Google is so confident it can deliver search-based advertising revenue to News Corp.-owned MySpace, that it guaranteed revenue of at least $900 million from 2007 to 2010 as long as MySpace hits certain traffic targets.

So, now does Dolan think Viacom can sell ads on a social networking site?

Maybe so, because there is a report today that Benchmark Capital-backed social network Bebo is being considered as an acquisition target by Viacom. I don't attribute a lot of value to reports that a company is considering an acquisition. Any responsible media or technology company considers hundreds of deals each year before finding a reason most won't work.

But, whether it's Bebo or another social network, the MySpace advertising deal was the proof positive that Viacom and other old media companies needed before making their own social networking acquisitions. Expect considerations to turn into offers in the coming months.

Technorati tags: viacom, bebo, myspace.