They also trademarked both “couchsurfing” and “couchsurfer” (https://about.couchsurfing.com/about/trademark/). Though I’d say that’s quite a disputable trademark. It’s essentially a common word from the dictionary, just written without hyphen or space. They can’t claim they invented it, so they would at least need to prove they have popularized it. We briefly talked about this on the Volunteers chat as well and here’s a rather devastating graph:
Difficult not to say they rather killed the popularity of the search term since they incorporated 
In any case, we use both “couch surfing” and “couch surfer” in our communication. These are common English words and there’s no reason to cede them to any company!