Doesn't matter who's first. But who's got the first patent.

He could get sued.

Patents and trademarks are different things, but I think in either case the idea of "prior art" would apply. In the U.S., you're granted a trademark automatically upon use. Brian should be able to say, "I've been using this since 2009" and be afforded at least a degree of protection. Of course, it's a lot harder to defend in court without a formal trademark, so he might not choose to litigate.

Actually, for a patent (and, as someone pointed out, it's a trade mark the orignal article is about) if there is documented proof of a previous invention (I doubt that would be a problem with IT) that is the easiest was to invalidate a patent.

For trade marks, fame does matter, but then again: documented previous existence of a smaller brand would be enough to stay. Having one large corporation buy a small existing brand, and marketing it beyond its original scope could put them in trouble, though.

woops, sorry I was sleeping!