Recently ran across a site, http://assignmine.com/, that's using a banner ad describing itself as "Wikipedia for assignments." (Will be happy to send a screenshot upon request.) Seems to me that this would be an issue with use of the trademark, but what would generally be the position on this?
It sounds like they're comparing themselves to Wikipedia rather than calling themselves Wikipedia, so it's not too bad. I'm not an expert on trademark law, though, so I don't know if it's allowed.