If Google didn't file for it chances are some patent troll would. I agree that patents are evil but sometimes they're necessary for defense (see Barracuda fighting back against Trend Micro)
Even if you are against software patents, you have to file them unless you want other people to use them against you. For example, if Facebook had patented this technique then Google wouldn't be able to use it without licensing it from Facebook, or spending a ton of money to dig up prior art.
I think its more about building a patent arsenal so that when other large software companies think about enforcing a patent against Google they will get scared off due to the risk of a counter action.
True, but you can't get to "no patents" via "more patents".
If Google are genuinely against software patents, they should not participate, and fight them by other means, including entering "patent disarmament" agreements with other large companies.
Organisations change, and the Google of tomorrow will probably be riddled with machiavellians and sociopaths, who consider the growing arsenal of software patents quite useful.
I thought about this idea for awhile after reading Link, but it would be very to theorize unless I had access to data for a huge social network.
And it's not just the most influential, but you can further break it down to by finding who are the early adopters, connectors, and evangelist of the group. This I think would be the holy grail for any advertiser.
The Google index algorithm is a trade secret. Whatever they published while at school is available and is often studied in search engine classes, but the most recent version algorithm is probably only available to only the most necessary people. PageRank is part of this algorithm but isn't the only part in determining where a result will fall.
This "FriendRank" algorithm will also be a trade secret. The patent here based on my quick scan is patenting the method that they will use to advertise to people using this FriendRank through Google's services or future services. For example, where it will be placed on the screen and how it will look.
And about Google: That's how it starts. Let's see when everyone's favorite Google changes their motto into "Don't be too evil".