How Twitter Should Make Money

1. They'd never describe it as this, but sign up as an advertiser and you essentially get all of this.

2. They're essentially doing this with their new interest based targeting for advertisers, i.e. mining users for interests and then letting advertising pay to target those interests.

3. Promoted tweets all the way. While they don't have follower count as a targeting vector yet, they do have everything from device and location, to gender and interests, to @handles and time of day.

They are already doing this