When I apply a new skin I have downloaded, certain changes made with messpatch are reversed. For example, adds return. Is this a problem with all skins, and if so, can I use skins to do the things that messpatch does anyway and thus eliminate this incompatibility?

i think you should only do some added function with mess patch now, as changing the way it looks + skins are not too good... its like doing a-patch and mess patch =p

That's because messpatch is telling WLM to remove the ads, then the msgplus skin is loaded which contains all the information about how things should be layed out, including the ads, so they are shown again. It's very easy to remove ads and other elements using msgplus skins, although skins won't be allowed into the skins database if they remove the ads. If you want to change one of your skins so there are no ads, you can find aNILEator's guide to removing elements at http://shoutbox.menthix.net/showthread.php?tid=79693 and "tailor it" to your own needs, although it'll involve a bit of knowledge of the layout files. You can probably find skins elsewhere (personal sites of forum members, skinning forum, etc) which will remove the ads, although then you can't have another skin applied, obviously.

If you're really stuck for the advertisements hiding (Not removing, removing the code can and will cause problems), you can find my original tutorial on removing the ads on the msgstuff forums

[Sidenote] ayjay it's ads there aren't 2 'd's in advertisement

Wtf, I removed them, hence the edit one minute after the original post. They came back