I registered the domain name hearts-rummy.com. I received a cease-and-desist letter saying “hearts” is trademarked. Can someone trademark “hearts”? I have not put up a webpage or posted any content. Is it safe to proceed?
Yes it is possible that someone has trademarked HEARTS, and sometimes companies have broad rights that surprise you, but there are just as many times where companies are over-reaching and do not really have the rights that they threaten to enforce. Without detailed analysis it is impossible to tell how broad the rights are that are being asserted. It looks to me like this is someone asserting more rights than they have, because you state that all you have done is register a domain name. I would not expect a domain name of two generic words to infringe a trademark by itself, without content on the domain name that is related to the goods or services of the trademark.
There is a valuable trademark lesson here. If your trademark is only a common term (as this case appears to be on the term HEARTS), it will be difficult to enforce, and lots of people will try to use the term innocently, and you will spend a lot of time and money chasing people that are simply trying to market their business, and are not trying to steal the goodwill from your business. It is possible to get exclusive rights to common terms in some cases (consult with an attorney and don’t use this as a general rule). On the other hand if you create a term or use an obscure word, there is much less chance other people will be innocently registering domain names with your trademark. For example NIKE is not a made up term, but it is obscure and not related to shoes or clothes (see article on GREEK GODDESS NIKE http://en.wikipedia.org/wiki/Nike_%28mythology%29). If you registered the term Nike.shoes.com, even without a web page, I would expect that you would get a trademark cease and desist from NIKE Inc., and I would also expect NIKE Inc. to win very quickly if you tried to fight it.
The real question is: what right does the company have in the term HEARTS, and are you infringing their rights? They might have the rights and could stop you, but they might not. You need an attorney to determine the answer.