For example, there's noonewantsit.com and its gonna drop and I want it. There's noone interested in this domain except me. Now if I goto a service like Pool.com and backorder this drop... will Pool.com somehow publicize my interest in this domain thereby potentially bringing more bidders into an otherwise un-wanted domain? I mean it would be in their interest to do so - but do they actually do that?
I think your fears are unfounded. Anyhow, if nobody wants it, it won't be picked up on the drop, and you can reg it when it becomes available again. Another thought is, you should maybe backorder it at both SnapNames and Pool, just in case somebody else might want it.
The way that the process of drop catching is so automated, there is a chance that the domain will be picked up automatically by either one of these dropcatching services or by domain tasting/kiting operators. It might be best to get the order in with a few dropcatchers if you really want the domain.