The Tweetbot for Mac alpha was already out before the limit was announced, I would bet they already had way more than 100k tokens registered at the API limit an

The Tweetbot for Mac alpha was already out before the limit was announced, I would bet they already had way more than 100k tokens registered at the API limit announcement. Tapbots has >135,000 twitter followers. They had significant exposure from many other sources too, like Daring Fireball which has >400,000 Mac + Twitter using RSS subscribers. Early adopters are more likely to have multiple twitter accounts as well, so they would have already registered multiple tokens.