I tend to prefer some additional sites as a reference for colloquialism and rude words in Russian:
- The alternative Russian dictionary - the eldest source on the net, but the quality of entries is rather erratic and updates have last occurred 2004.
- Russki-mat.net - a comprehensive dictionary of Russian slang with up to date information that I have failed to find elsewhere in English (and additional dictionaries for French, German and Breton).
My other sources are in Russian only, I am not sure whether they would be of interest here.