But it has become increasingly clear that Facebook is modeling personal relationships, not relationships based on attention. Thatís the crucial difference between Facebook and Twitter at the moment.
I have approximately twenty times more Twitter followers than I do Facebook friends (Me on Twitter | Facebook). I doubt I could ever have as many friends on Facebook as followers on Twitter, because if I did I would have to pay attention to all of them, all of the time.
On Twitter I donít even try to follow everyone because I donít have enough attention to do so (I tend to follow people Iíve met). Similarly, many of the people I follow donít follow me back. Why would they?