Of course. Facebook and Livejournal limit the number of friends. There is precedent for setting a limit. - Morton Fox

Why should there be a limit? Mostly people are following Scoble, because we're interested in what he has to say. He follows many back and people appreciate that he might be interested in what they have to say. Why should he be limited in the audience he wants to follow? Shouldn't that be his call? Why should he be penalized for having a large interest in those who have interest in him? - Liz Polay-Wettengel

When the amount of people you follow is higher than a certain amount (I'm going to suggest somewhere in the hundreds, definitely not the thousands), you aren't paying attention to your followers' posts, you're not interested in them. You will never read what they have to say, you're just following them "for show." I like to reference Dunbar's number (http://en.wikipedia.org/wiki...) as a related theory that there is a limit to the number of people you can reasonably have a real interest in. - Sarah