I don’t feel like blocking users who only edit their userpages should be allowed. Yes, the main focus should me contributing to the wiki, but I think blocking is a bit harsh. In my opinion, the majority of those users have just joined and are not familiar with user pages, message walls, etc. If they happen to stumble upon this wikia looking at pages, I think it would be reasonable for them to incorrectly assume that it is acceptable, and then not be able to see ACME Heads’ messages on their wall, due to their inexperience. Also, I have seen many users on numerous wikis who prefer to introduce himself or herself properly, then start to contribute. Thirdly, I personally think that forbidding a user to edit their user page freely makes them feel unwelcome.