I've modified the cooldown time on individual songs at the behest of some people. It should be half as long now, so songs should hopefully be requestable more often now than before. Kilim thinks this will make people listen to r/a/dio more. If you agree, please comment. If you don't agree, please comment.
I've also fixed a very long standing bug with requestability. You should now no longer see songs as requestable only to click on them and have it tell you that it's on cooldown. If this is still happening to you, tell me about it and I will ignore it for a couple months until I fix it. Thanks.
Update: I've now added a cooldown timer to the search result page. Do keep in mind that it's an upper bound; the song could come off cooldown before the given time. (In hindsight, the system should have been designed better to prevent that, but eh.)