thanks for all the suggestions. I will try them and I suspect some or all of them will work for us.
for what its worth, blankposting is certainly quite civilized. Users have a lot of fun with it, sometimes they even have impromptu contests to see how fast a topic can be filled with posts, or how many blank posts can be posted in a row before someone breaks the chain. And it certainly creates a lot of engagement and fosters a fun community atmosphere. You might be surprised at how much entertainment users can derive from such simple features.
thanks!