Just because it is in court, does not mean it's not that simple. If I start selling shirts in 2006 in the US that say NIKE for example, and Nike finds out about it, they are going to send me a C&D. If I continue, they are going to take me to court. I won't win. Why? Because the law says I can't use someone else's trademark after they register it. That's simple. The reverse is also true. The law says that if I started selling shirts with Nike on them in my hometown of Nashville before Nike applied for their trademark registration, then they were granted registration status, they still would not be allowed to sell Nike in Nashville. If they did, I could send them a C&D, then take them to court. Simple. Just because to sides disagree about an issue, does not make the issue complicated. The law is simple on the issue. Use your mark in your market, you own it in that market. As long as you were the first to use it there. I will check this case out in depth, but I don't know who is sueing who. If the lady was using it first, I hope she's the one sueing, because J Lo's people should have known about this lady. When you file for the trademark, they even ask you to affirm the fact that you have gone through reasonable measures to assure that noone has a common law trademark. If this lady can prove that she was using it before J Lo, she could easily prevail in the case. But make no mistake, simple things get sued over all the time!