Meanwhile, you ask a question or two about it (size, smoke free home, anything else not answered in the ad) or even say "When is a good time to look at/pick this up? Will pay cash."
Crickets. Online classifieds are a lot more frustrating than they used to be.
Not sure if they already sold it (and still left the ad up) or if it is a scam and they don't reply because my offer (see in person, handle pickup myself).