Strive to promote domains and not just a domain.
I don't buy the notion that people who have experience building sites know where to look for domains, they aren't going to google it.
Then why Godaddy, Domain, Namecheap and other registrars spend so much on google and other online ads?
They are not popular enough?
Type in anything "domain" in the search box and watch what comes up.
That being said, to make your ads worth it, you must resolve 4 technical issues.
1. A website with your portfolio of non-mediocre domains.
2. Effective search mechanism with multiple category selection, complex keyword combination search. From my log, visitors oftentimes search for very unpredictable combination of words, e.g. "nice domain for restaurant in colorado" or this: "money making domain name". So your search engine should be able to split the words into parts and search the database recursively.
3. Landing pages with buy now/offer form, visible email address and telephone. From my experience, even if interested, about 40% will not fill the form. They will email you directly or call.
4. On the lander, be sure to have options linking to popular marketplaces - to the exact page, where the particular domain is listed.