deadsea - 1:37 am on May 8, 2012 (gmt 0)
I don't have any community features on this site currently. In fact, I added the ability to login for the translation feature. The top translators page is a great idea. Should be easy to implement and give kudos to those that have helped out.
I'm not too worried about tone. Even varied tone is going to be a big step up machine translation. Once the international sites get enough users to warrant professional translation, I'll go that route. The Spanish, French, and German sites are getting to that level now. They each have over 100,000 visits a month. Most of the languages only have a couple thousand visits a month though.
For translation approval, I have been machine translating back into English, just to be sure that there are no swear words or obviously off topic submissions. I'm assuming that if somebody took the time to improve a translation and it passes my reverse translation sniff test, then it is actually an improvement and I accept it. I have no way of knowing which of two humans does a better job, but so far I've only had corrections for machine translated text, so that hasn't been an issue. Before I implemented the user translation feature, I occasionally got feedback from users through the contact form about bad translations (and sometimes suggestions for improvement), I'm sure that will continue to happen.