BillyS - 6:29 pm on Mar 21, 2012 (gmt 0)
Good point Reseller, I know a lot of webmasters have been hard at work paying for, or encouraging, "likes" and other social signals. Perhaps this might be added to your list.
For example, Google may have been looking at this as a quality / engagement signal, but now tweaking that dial to eliminate some of the gaming we're seeing.
BTW - I notice that a lot of the big brands jumped on that bandwagon too, offering what look like incentives to click that "Like" button.