Actually, on DW, you can make a sticky note in communities. Not sure if this is something you want to do but it's an option.

If you go to this page: http://www.dreamwidth.org/manage/settings/?cat=display and put the url of this post in the field for ID or URL of post to make sticky, this post will always be at the top.

One thing I've noticed, however, is that it will duplicate the post on the Recent Entries view -- you'll have a sticky post and the post as it is regularly. They're the same post (ie if you comment on one, it'll show up at both) but they just duplicate. I'm not sure if this is a bug or feature.