>>Verify with who? The person who posted the ad, or the operator of the website?<<
Let me answer with a question. If you see an ad for free puppies on a bulletin board at your local restaurant, but there is no address or phone number, do you ask the restaurant manager where the puppies are?
Answer: He is likely to say, “I never look at that thing. It is just a community service I provide for my customers to buy and sell stuff. But if you see anything there that offends or there is no contact information, feel free to remove it.”
Come to think of it, if there is no contact info in an ad, here is what Craigslist posts in it:
“No contact info? if the poster didn’t include a phone number, email, or other contact info, craigslist can notify them via email.”
But it doesn’t say the poster will contact anybody back. Or that the email is not an anonymous hotmail account, etc.
I would ask the restaurant manager if he/she had any other information, yes. In this particular case, the people knew where the puppies were, so to speak.
“I never look at that thing. It is just a community service I provide for my customers to buy and sell stuff. But if you see anything there that offends or there is no contact information, feel free to remove it.”
If there were something criminal on the bulletin board, and it came to my attention, I would approach the manager and let him/her know in no uncertain terms that, since the bulletin board is in his/her restaurant, I would expect him/her to keep tabs on what is posted on it. If he/she doesn't have time for that, then the bulletin board should be removed.