It would be super cool to be able to click the drop-down bar for selecting where to post, and then pick multiple options. The trouble with that, though, would be how to deal with tags. Does one particular place get tag dominance, are tags disallowed in a post you're crossposting, or will there be multiple tag fields with one for each posting location? Disallowing tags on the initial post seems like the simplest option, with the latter as probably most preferable. Hmm.