haha.. on your last point.. yes we thought of using dustbusters (with an s) and realized many might type it wrong... :P...
On the votes, they are ONLY cast on your dust... if you have dust, it will get upvoted... So while you have given me another idea of another project, I must inform you that your dustsweeper subscription will only take care of your dust... (ps... You can tell those that you interact with to set up an dustsweeper account and they will be paid on any small votes that you may cast)
I do like your idea of going downward interaction, I will give that some thought and see what we may be able to do with that brilliant idea! :)
Oddly enough I had my question answered when I saw @dustsweeper in action - works just fine.
Good point on the plural, it does seem kind of unnatural, and so ...sweeper is better.