I suppose more details would indeed be helpful. My product is an iPhone app called "What's Open Nearby" and they have a website called "What's Open", both of wh

I suppose more details would indeed be helpful. My product is an iPhone app called "What's Open Nearby" and they have a website called "What's Open", both of which show opening hours for stores. 1) Yes. 2) We don't claim to be the other service, and have never had anyone confuse the services. 3) Possibly. We have bought domains with that name, it's our Twitter handle, etc. I don't want to fight it in court though. 4) No. The words are commonly-used and there are other similar services that use them (for example, Open Near Me). Plus, they only registered the trademark a few weeks ago (but have had the site since 2006). I'm thinking of proposing that we put a statement on the app's website that it is not associated with them. I've seen that done many times.