The public eventually learns patterns in domain naming. The most obvious part is the TLD, and they pick up on that fast. I think most people think that .biz domains are associated with cheesy fly-by-night companies, for instance.
But I think they learn patterns in the main part of the domain as well.
To the extent that certain naming patterns are used for domain parking, link farms, etc. I think the public learns to recognize them.
It would be easy enough to do a survey. Give people randomized lists of, say, 10 domain names. Have users rank them in terms of expected usefulness.