There's no anti double post mod! I don't even know if IPB has something like this. More useful for advertisements than anything else, really. Basically all that mod does is prevent you from double posting. For example say if you bump up an advert, then you accidently bump it up even if only a few seconds later. The second bump would just appear under the last post you made, kind of making it look like you edited your original response when you really didn't. Sort of hard to explain. I kind of like that mod.