[kh99]

You can of course turn off your external feed. You can also limit the length of the descripion so they can't get the entire article from the feed (it uses Settings -> Options -> Forum Display Options -> Length of Thread Preview Text, but this also affects the forum display).

Also, the feed only works with public forums but occasionally someone asks about having it be members only (but that makes it a lot less useful because people have to be logged in to use it). Anyway, you could search for that if you're interested.

Other than that I don't know what you could do. Really, anything you make visible to guests can be stolen (and even if it's members only, it's easy enough if you allow anyone to register). The feed makes it easier, but even without that, if someone wants it they will get it.