I am not a mod or anyone official, but I think this comm is a really good idea. I know I'm very grateful to the kind British folk who correct my Americanisms and tell me what foods would be appropriate for certain occasions. And I know I grimace when I read fanfics set in the U.S. and a supposedly American character runs out to the "car park" because he remembers he has a date at "half seven".
If you live in the U.S. or Canada, consider joining the comm. To be really helpful, they'll need people from all over, since language and culture are often regional. And maybe plug it in some of your other fandoms. I saw this in a House M.D. comm, but there are a lot of other fandoms with a North American setting and fans overseas. (For that matter, even in British fandoms such as Doctor Who, authors often set a story in North America, or crossover with an American fandom.)