Rule of Twitter: When one million followers is actually... zero

From Twitter account of David Pogue of NYTimes:

Pogue 1 million followers today. A little scary: that's more than read the Times, more than watch CNBC, more than read my books... NO PRESSURE! 21 minutes ago from TweetDeck

Pogue via @ridgeley: 1M followers for @pogue, but most are spam. [DP sez: Probably true. Rule of Twitter: # of followers, divided by 10?] 8 minutes ago from TweetDeck

Pogue OK, you guys are telling me: 1/2 of my 1M followers have moved on. 25% are spam. 25% are auto-follow. So that comes to... NO FOLLOWERS! :) 6 minutes ago from TweetDeck