I'm new here on the forum, but not new to subtitles. I read with great interest this thread, and was happy to see thinking, earnest people, who take this at heart. That's why I decided to register and be of help if I can.
I like to watch Indian movies with my family and I've spent hours and hours editing and sometimes guessing. No, they were not machine subtitles, at least I don't think so, because they share some Indian mannerisms and common errors (I think I've learnt much about the syntax of Hindi!!!) but I didn't want the kids to be exposed to bad English. OK. Sometimes I left something as it was, because I couldn't understand at all what the translator meant, not even after watching the scene in the movie. Sometimes a letter was routinely replaced by another, for instance almost all "h" by a "b" but not all, because otherwise I'd transfer the file to Word and use "find and replace all" and be done with it. Whenever I was too tired to correct the whole movie, I left a part undone, and it really spoiled our enjoyment of it. Still it's better than nothing at all, as we don't understand Hindi.
So I'm grateful to the anonymous bad English speakers who did their best to help others.
I now have dozens of painstakingly corrected (and many times also painstakingly synchronized) subtitles, but I don't know whether uploading them would be any good. I'm shy of putting "corrected" on the title, as I've still left some things obscure, and someone might bash me for those, not knowing how bad the original was, and what a huge improvement this one is. I suppose one could add some comments, and ask speakers of the original language to improve on these. But how do you keep track? What should the next improver add to the title?
So yes, I'm all for a wiki kind of thing! There each one can add their bit.
BUT machine translations are another thing altogether. There, you really don't understand a single thing. I'm Greek, and once a foreign friend tried to send me an e-mail in Greek, translated with Google or something. I think I risked a heart attack or death by choking, with so much laughter - I almost fell out of the table, family rushed to see if I'm all right. I am grateful for that, because it was a rather boring and sad day, and laughter is good for health, but what I mean is that machine translations are not translations, they are a big joke, and in my opinion should be completely banned/removed. Even when there's nothing else available, because it is not better than nothing.