My policy is "unless you talk to them physically, they don't exist." That may sound weird, but those who are truly interested, not just window shopping, tire-kicking, looky-loo-ing, whatever, will call you. A member on here saw an ad I had for a pair of cochins on bestfarmbuys and rather than putter around with silly emails--do you still have them? Will you take X in trade? Where are you? Can you send me a picture? Can you send me a better picture?--they just called, got the chickens the nest day, paid cash and let me know that they're doing OK. Emailed later b/c she had a question, but that's understandable.
If someone wants something bad enough, they will get up off the computer and give you a call