Friends: How many is too many?

Okay, I'll admit it: I don't have time to read more than half the tweets and status updates sent out by my friends on Facebook and the people I'm following on Twitter. And I only have 200 on Twitter and 350 on Facebook. In fact, on most days, I probably only read one third of the chatter (and I don't mean that in a pejorative way). There have been a few pieces floating around the Web lately that say the average person can only keep track of about 100-300 people maximum; after that, it just becomes white noise. (And did you know Facebook limits you to 5,000 friends?) And it also works against the very idea of social media: that you're creating a community to "interact with," (that's the 2.0 model) not amassing thousands to "speak at" (the 1.0 model).

So what about all these friends of mine who have 1,000 Facebook friends or 2,000! What about my Twitter followers who are following that much, or even say 25,000 people? Clearly most of the followers/friends have been "hidden" or banished to a far away tweetdeck column that they don't read, right? Because it would be impossible to read any significant amount of such volume. So if that's the case, here's the question: Why have 2,000 friends on Facebook? Why follow 25,000 people on Twitter?

One theory: it's impolite not to Friend or Follow someone who has initiated the same. Or how about this theory: it's all about the numbers--the more you have, the more popular you are - and who doesn't like to be popular?

What's your take? How many friends or followers do you have and how many is too many? We'd love to know how you handle the issue and what you think about all the white noise.