There are always questions when it comes to legitimately using other company’s trademarks and brand names in domain names. Companies don’t like it when unrelated entities own domain names with their marks, and they often resort to UDRP filings or litigation. It’s generally pretty expensive to defend and can cause far greater legal problems.
One website that seems to be doing just fine is PeopleOfWalmart.com. The site has drawn millions of visitors since it launched in 2009, and it receives a ton of submissions. There have been questions of privacy issues, but it seems that Wal-mart has left the site alone for the most part. In fact, they filed a UDRP for a typo of the domain name, PeapleOfWalmart.com, which the company won.
In any case, it appears that Wal-mart has left the site alone, and in filing a UDRP for the typo, it probably tacitly implies that they don’t think they can do much about the real website. In any case, this seems to be an example of a website where a trademark is being used without trouble. Incidentally, the folks at Break.com released a People of Walmart video, which you may enjoy if that’s your kind of humor.