Let me explain something.
Using Varlin's reply as an example: DNJournals and eBays
1. DN is a well known and generic acronym in domain name industry, well, "e" can't describe a specific industry intuitively.
2. There are 319,000 .com websites with "Journals" at the end of their domain names. However, only 2,030 sites with "Bays", so this is really not a suitable example.
From this point, wmloz's example fords.com, chevys.com, or rollingstone.com vs. rollingstones.com are not suitable as well.
DNForum and DNForums would be a good example, would you blame a DNF member who owns DNForums (I am glad to see Adam owns DNForums though)
I didn't think the potential issues this much when I bought the name from another U.S domainer, I have sent a lot of inquiry emails with offers to different DN domain owners in this niche and many replies with BIG asking price in low - mid $xx,xxx range. Well, DNJournals.com asks for $80, that's reasonable enough to me and it's a perfect name to my plan - a directory site links blogs/journals/tutorials site about domain industry (inc resell if I can find a better name later). Then I checked USPTO before the final decision just like I used to do, I didn't find the TM info on DNJournal and DNJournals, so I bought it. However, I could be wrong, if Ron owns the TM of DNJournal and he wants the plural version, I would be glad to give it to him. Although I'm a newbie in domaining, I personally respect Ron like all experienced domainers do. But, maybe just like Creature says: The plural is completely trash, Ron won't want it.
Well, with all friendly advices in mind, I started again to find another generic DN name for my plan, though I doubt that I can get another suitable name for $80. I'll try.
Thanks again.