The process for filing for a trademark for a domain name is similar to any other name in terms of comprehensive research and analysis being a necessity.
Comprehensive research consists of looking at marks that are similar in Sound, Appearance or Meaning in the pending & registered Federal AND State trademark files as well as the US National Common-Law files.
There is one big caveat when it comes to trademarking domain names and it has to do with usage of the domain name.
"A mark composed of a domain name is registrable as a trademark or service mark only if it functions as a source identifier," so says the USPTO. Okay, but what does that mean?
Basically, as long as your domain name is the name of your product and/or service, it's likely registrable. Let's look at some examples to illustrate this:
Example: Our primary domain name is www.tmexpress.com but the name in which we conduct business is TradeMark Express, therefore our Federal trademark registration is for TradeMark Express and not our domain name.
Example: The online seller, Amazon.com, has a Federal trademark registration for Amazon.com because it's the name under which they conduct business.
If you're not sure about your domain name, please email me and I'd be happy to assist you further.