Douglas Mann of Popular Mechanics magazine took a similar approach. He took a somewhat more thorough look at his followers and those of a colleague and found that anywhere from 20-50% were fake or spam. He cited another study by a company called PeerAnalytics which found that only 35% of the followers of the average Twitter user are real people.
What does it all mean? To me it bolsters my opinion that Twitter is an unlikely vehicle for effecting sea change. Still, some feel that changing even one person's mind about an important issue is worth it. That's fine. But let's keep it all in perspective.