We just post a list of frags that we think would be good contenders. I personally like it when people suggest frags that are widely popular among Basenoters so we can get the most participation as possible. Then the votes are counted and there will be one scent which reigns supreme. Then we pick a date a few weeks from when we pick the scent, so people can obtain decants or samples if they'd like to.
I wait for the poll results and will decide then. If the winner is something I own (sample, decant or bottle) and like, I'm in!
(The female forum just finished the 13 part Scents of the Decade Day series yesterday, so...)