Before Christmas, I begin the challenge of making a list of all my 5000 friends, because I noticed a decrease in the average views per post and that a lot of my friends were inactive for a long time. I am still in the middle of this process, but I can now say that in the first 1000 friends I checked, about 300 were gone from TSU for more than 15 days, with a lot posting nothing for more than a month. Being that we have a limit of friends, it is very important that one checks this once in a while, deletes the users that are no longer on TSU and also delete and report the ones who post innapropriate contents (found a lot of sexual content, and even more of religious fanatics). In fact, as I've started replacing these "bad" friends by new ones, these ones chosen with more attention, I immediately noticed the view per post numbers going up again. Also my main message board got a lot cleaner and nicer.
I truly think this is a good way of improving your TSU experience. It is a bit of work, but on the long run can be the difference of having a good or mad experience on TSU. I hope to have this checking done by 2015 so that this next year starts with a blast!
Best wishes to all you TSUsers out there!