sundaridevi - 2:35 pm on Mar 18, 2012 (gmt 0)
You can buy twitter followers and mentions, Facebook likes and fans, Stumbleupon likes etc.
Sure you can, but it would be much more difficult to make a social mention go viral. When you have a facebook post that gets shared 50 times and only 5 of them were your fans and some of the shares are & few degrees removed from you, then search engines would recognize this as a vote of confidence. Bing probably has more ability in this area due to their ability to access facebook data. Maybe that's why the Bing guy talked about social so much more.
Most likely a simple first level post is worth much less. Making a StumbleUpon post go viral is even more difficult without really quality content. My conclusion is that you will get a better return on investment by building good content and I think that's the way search engines want to see it.
Incidentally, google has a -100 penalty for tweet spam. Which is to say hourly tweeting the same url over and over again with just a few different tweet text variations. But it only lasts for a week or so. This is not speculation.