Q: Can I grab an expired trademark and sue the former holder for still using it on his website?

A: It is important that you understand the difference between a trademark registration and the underlying trademark rights. Trademark rights arise from using a mark in commerce in conjunction with the offering of products and/or services. Once a party actually uses the mark in commerce, they have acquired trademark rights, assuming the mark is one that is eligible for protection and is not confusingly similar to another mark. Then, as long as the holder of this mark continues to use it, they continue to hold the mark. This is true whether or not they ever formally register the mark.

Registration is then really a supplement to the underlying rights. Registration gives public notice of trademark rights, gives you and enhanced set of rights (for example, you generally have to have your mark registered in order to enforce it in federal court), and gives you a presumption of validity, along with a host of other benefits. However, again, registration is not mandatory. As such, if a registration is allowed to expire, as long as the party holding the mark has not abandoned it, they may still hold valid rights to the mark. Abandonment is a complex topic that involves a number of factual issues

Your question triggers a lot of other issues outside of just the abandonment issue, as well. Some time should be spent analyzing whether or not your use is actually conflicting with the other party, etc.

***Please note the important disclaimers at the bottom of this page.***

A: As Mr. Gerity mentioned, there is a difference between trademark rights and trademark registration.

For your particular case, some time need to be spent analyzing the merits of the infringement, and to help you figure out whether your mark is actually conflicting with theirs or infringing on their mark.