A number in the title doubles my unlock rate. 158 posts say so.

I sorted all 158 paid posts by whether the title contains a specific number. The group with a number converted at 7.32% against 3.41% for the group without, on similar traffic. The five best titles, the pattern in the 111 posts that unlocked zero times, the queue-ordering change this produced, and the two reasons the result may not transfer.