It is a German team, a German "Verein", and of course through that tradition a German HP. I don't expect the projects to have their Sites in German, French or any other main language from the beginning as well, English only if they are in some English speaking country is fine first, Spanish for Ibercivis, Dutch for Almere, Japanese for Tanpaku, whatever. It's fine to put some main content in English as well, and with RNA World there is too much English, far too little German now, but English does definitely not have to be the main language of all websites.

Concerning the off-site forum: RNA World and Yoyo@Home are not the only ones with this setup: WCG, Simap, Spinhenge, CPDN, FreeHal, Ibercivis ahve it, and even Folding@Home outside BOINC has the forum completely outsourced. The BOINC forum software is fine for Projects, that don't already have some software running or don't want to bother with a real forum software. But it definitely isn't as good as a real one, and I prefer only one forum per project, I don't like the CPDN setup, with two different fora.