@mirrors, I think I figured out something about the reputation score. I looks like your reputation is dinged if you follow anyone who is below your reputation score. I am unfollowing anyone with a reputation below mine, to see what happens.
This makes sense from an algorithmic standpoint. Probably there's a computation of the differernce between your rep, summed up across all people you follow.
The converse I think is also true. The more people with a higher rep than yours that you follow, the better your rep should become. This, of course, severely penalizes minnows and anyone else with a low rep.
Those people who just follow everyone will be only spinning their wheels because they will most likely be following people with a very low, or negative, rep.