The other day, our English to Russian Senior Translator mentioned gramota.ru, a very comprehensive Russian grammar/spelling/style/usage resource. Does such a resource exist for every language? If you use something similar when translating, please let us know about it by adding it in the comments below.
I'd also love to hear about other learning or skills development resources that are interactive and collaborative, for example, lang-8.com. Has anyone used this? What did you like about it? What didn't you like? Are there any other learning tools like it?