Pay your fee, you get not only an attention boost, but the ability to un-boost blues. If the net result is 0, the Nash Equilibrium is that everybody pays.
Look how many people "#BlockTheBlue" on twitter right now. Just charge them to make it easy. The real value in someone who's willing to pay to be seen isn't in their 8$ subscription, it's in the 100 other people they incentivize to pay you to shut them up.