tedster - 4:55 am on Sep 16, 2012 (gmt 0)
I'm somewhat familiar with the full data from Twitter's "Firehose" and I know that there is both a lot of intelligence there as well as some big fat "tells" about which data to ignore.
One key to identifying social spam is in the area of sentiment analysis. Google has already working hard on sentiment analysis for years (particularly for News search). But once you get good sentiment analysis happening for a given type of data, then you've got one heck of a tool for all kinds of areas. In social networks you can see patterns just jump out of the data pile that identify the fake networks. That's because they actually ARE fake - they don't show true human diversity.
Here's another one. Have you ever watched account after account start following you on Twitter and then all of a sudden all those accounts are deleted in one swoop? Twitter is not sleeping on the job, either.
So is Google using social authority in the SERPs right now? Maybe just bit, but not really so much. But are they working on it? Oh yes.