Sorry I was traveling so I am just now getting to this.
Community depends so much on the area, I am in a small town and have been here since last October but have yet to make any friends I really click with. There are some expats here who I have met up with but no one my type yet.
Learning the language will be a HUGE advantage to you. Most people under 30 speak decent english but over that, in my experience, is really hit or miss.
As for what I wish I knew about the culture, at least in this region, its very closed and very private/paranoid about personal information but most people will gossip openly about others- just not tell you much about themselves. Sometimes it feels like highschool all over again. I had some major run ins with my DH family when we moved here because I posted some holiday photos on my flickr account and they felt I had 'violated their trust', needless to say, this isn't just their feeling but a lot of peoples here.
I would be happy to talk to you more about anything, feel free to PM me and I will give you my email address or IM name