Past week toDude rained a lot of coins and we got a lot of lurkers, people just wagered 1-2 levels and waited for the rain and normal users started complaining about it. Thus I implemented a simple rule to wager 0.01BTC in the past 24H to be eligible for rain. As it in the test mode (running only few hours) and only on BitDice there's no update yet except chat. I'm still thinking on how to improve it and maybe implement variable wagering amount depending on user level. But I always stated that RainBot intended to active players only so those updates are correct.
As shown by the posts above toDude was insanely generous while on his winning streak. And I fully appreciate everyone's frustration with people who don't chat, don't play and just scoop up rain.
I actually think this rule is just fine (and even if I didn't - your site your rules) but you should let the chatters know so when the inevitable crying starts, "I'm level 7, chatted, bet, and didn't get rain, whaaaa...." someone can explain. It would also be more welcoming to new members if they knew the rule as well. (I presume you want new members!)
I also like the idea of testing it out on one site before moving it to the others, the others don't seem as active, though that may just be a function of toDude's awesome run.
Thank you for responding and explaining!
Good Luck!