Every serious SEO has probably heard of digg, stumbleupon, facebook, myspace and youtube before.

When it comes to viral marketing/link baiting in German, I believe the same principles hold true as for doing the same thing in English (in the far Eastern markets with a completely different culture users might "tick" differently and thus the same techniques that work in the US might not necessarily work there).

However the main problem I faced (and am still facing!) when trying to do SEO in German is that the German web is a bit different than the English speaking web as things such as social bookmarking or blogging aren't as popular as they're in the US yet (yep we lag behind a bit).

Plus there are different sites used for social bookmarking & so called "web 2.0 stuff". For example few German users might used digg or stumbleupon as it's not very well-known here, so it probably doesn't make much sense to try to target these sites with a German link bait article (surprisingly I just saw a German site that had a link from digg, though but it seems to be rare).

One site is extremely popular in German, too, though:

Youtube - all of my friends use it daily. When it comes to video it completely dominates the German market. I think it's probably used as much as in the US.

The second most popular site for video here is myvideo.de
I've heard the name mentioned quite a few times and seen TV commercials for it before, however Youtube still clearly takes the cake (none of my friends really used myvideo). But if you've created a viral video, why not launch it on there, too?

As for facebook, we have a website called studivz.net (or .de) which is basically a clone of facebook. There used to be a lot of controversy about it b/c they were said to be using the same design/code that facebook used (w/o renaming some (any?) of the English filenames in the beginning), but I cant really tell if that's true as it's not my area of speciality. There was a lot more controversy about this site (hmm maybe some of this was actually just linkbait?), but it's used by pretty every college student out there. I only registered b/c of group pressure ^^ and in my city pretty much every single college student is a member at that site (I can't think of anyone who isn't off the top of my head). The list includes even people who don't really use the internet on a regular basis.

I haven't done much with it, yet but I know one can create groups there (and there tons of completely useless groups :-)). Each time somebody writes something new in one of those groups every member gets an e-mail note about that. I'm only in 2 groups and only gotten 2 e-mails, but it seems as if the average studivz user is in 20+ groups :-). Becoming a member of such a group often is really just a trendy thing to do to show that one can relate to something (example: "p diddy's mom looks like a [offensive word]"). However I think there are also some groups about things that people are really interested in to exchange information..pretty much like forums (Ill have to dig deeper into this, obviously).

Another site I've come across quite a few times while doing link analysis is called misterwong.de

It seems as if this was the most popular German bookmarking site (by far?).

Here's a list of 29 German bookmarking sites:

http://www.viralandbuzzmarketing.de/...okmark-button/

Unfortunately I don't know overly much about the German social bookmarking scene, but I'll sure learn more about it in the next couple of months and will continue to add information (including my personal experiences) with these sites.

I think the main thing that changes when doing SEO in German instead of in English (other than switching languages of course :-)) are the social bookmarking/blogging scene as completely other sites exist for that/are popular on the German-speaking web.

EDIT: There's also a site called xing.com which is pretty much a clone of linkedin ...extremely popular in Germany.