I started to do the mental arithmetic on Robert Scoble's claim that he "follows" 20,000 people in Twitter. Pondering how many messages a day 20,000 can generate. If I assume 1 message per day per person (from the people that I follow that would be way low) that would be 20,000 messages per day to read, scan or somehow process. Since there are 1440 minutes in a day that would imply 13.8888889 messages a minute -- one every 4 to 5 seconds.
Given that there must be some time in a day for sleeping, eating and other necessities and given that Robert has many other things to do other than pay attention to Twitter the message process rate must be way higher (perhaps two or three or more times as high). So that is approaching 1 or more messages a second. I know there are claims that Robert is a cyborg (though from personal knowledge that seems not the case) so that seems not a plausible explanation.
I think then that Robert's claim is somewhat suspect (of course his definition of "follow" may be different from mine -- or my math may be wrong).
So come on Robert 'fess up. Are you really "following" 20,000 on Twitter - at least in any real sense of the word "follow"?