There are several sites that promote themselves by getting mud players to vote for their favorite muds. Since we think New Moon is the greatest, we like voting for it and seeing its popularity rating advance. If you like New Moon also, why not cast regular votes for it to show your support? It's easy and free, with a few simple rules that vary by the particular site collecting the votes.
There's no in-game benefit to voting. We do it because we like to see how popular we are, and the only thing you get by voting is a share in that greater popularity.
The Mud Connector
The Mud Connector allows each person to vote once per 24 hour period:
Top Mud Sites
Top Mud Sites says it allows one vote per person in every 12 hour period.