Deep immersion

I decide to make a short link list for Runet explorers. I suggest, it will be five points where you start your deep immersion in Russian Internet. So, what we have:

1. Search engine - Yandex
2. Dating service - Mamba
3. Goverment resource - Kremlin.Ru
4. Culture resource - Hermitage Museum
5. Ru-En Translator - PROMT

I am ready to see your suggestions and addings in comments.