that to my knowledge has no trademark associated with it
Well this might be a good time to expand your knowledge. What any random poster on Namepros does to figure out whether there is a trademark associated with a domain name varies wildly, and is often based on folklore. So, it's tough to say in any given instance whether your effort will be appropriate to the circumstances.
Should I respond or ignore? Should I counter?
It's often not about whether to respond, but how to respond. If, in step 1 above, you find that, for example, a company started using the mark in 2015 and you've had the domain name since 2011, then this is an opportune time to mention, somewhere in passing in your reply...."I've had this name since 2011, and..."
And then it depends on what sort of name are we talking about. Obviously, you registered it for a reason to believe it was valuable, and if the reason has nothing to do with the possible mark, then it's worth mentioning - as any competent sales person would - why you think the name has value.
For example:
Let's say you registered Dogbreath.com in 2017 because you thought it would be a great name for dog treats that improve dogs' breath. Now, let's say that you find out, by doing a
GOOGLE SEARCH which is free and requires no technical skill or time investment beyond a fraction of a second, that some company started last year and makes energy drinks called Dog Breath. Then, and I know this is going to knock some people for a loop,
TELL THE TRUTH:
"Hi, thanks for your inquiry. I registered this domain name in 2017 because I think it would be a great name for dog treats or oral care products to improve dogs' breath. Because of that, I believe the name is worth at least $XXXX."
You would then have done several things for yourself. If they were planning to file a UDRP based on their 2020 trademark for energy drinks, what they wanted from you was just a straightforward price quote. They would then use that as an exhibit in their complaint and claim your price was premised on their mark. By sending the response above, you have now screwed up that plan. They will leave your reply out of their UDRP filing, and you can actually nail them to the wall for not mentioning it in their filing.
Things that are dumb to say, include:
"I registered this for a project I'm working on" - yeah, bullshit. People who have had a domain name for ten years and claim to be working on a project are believed by nobody. On top of that, if things really get interesting, you could be put under oath and asked about that "project" of yours, and it doesn't help you to have to say, "Oh, I just said that because I'm full of shit." It doesn't make you credible.
"I have someone else who offered $xxxxxx" - Also not a good plan for similar reasons.
So, here's today's takeaways:
1. If you don't know, then try to find out what you don't know.
2. Don't say things to people that aren't actually true.