Don't know where you are from. I know one large Dutch IT community called Gathering of Tweakers. Although it isn't a N900 community the news site regularly publishes about Maemo and Nokia N900. The forum, quite large, contains a Maemo / N900 thread and this is pretty informative and alive. The advantage is local/own language, useful to hunt device in stores, talk about keyboard layout, data plans. Disadvantage is that other places are simply more informative, complete, quicker with reports, and other cultural viewpoints are refreshing. It really depends on why you want to go to a Maemo or N900 community.