1. Accounts are sold because the Signature Ads they can run pay more.

2. People post meaningless drivel to get paid for their Signature Ads.

3. More people posting more meaningless drivel means more hits on the site.

4. More hits on the site means Theymos can rake in more income from his own site ads.

5. After taking in millions of $ worth of BTC "donations" from old timers, well, Theymos just needs to suck a little bit more out of this "community".

6. Use raised funds to pay "moderators" who help steer Bitcoin development in the direction his friends at Blockstream want/need it to go.

7. Sleep like a baby, content that you have been an excellent steward of this decentralized and trustless system.