Here are some staples of the 2000s runet that I recall (haven't been there since then really)

- bash.org.ru, IT and programmer humor site that produced some classic memes (I know of the American one, but this one was its own thing)

- Masyanya, popular flash cartoon series.

- Padonki internet slang, Russian that is distorted, misspelled and vulgar, similar to leetspeak.