But is it also a threat to public safety?
Right now a man alleged to be the Craigslist killer sits in a jail in Boston, accused of robbing and assaulting two women he met on that site - and killing a third.
It's not the first time something like this has happened.
Recently, a New York radio host was found murdered in his apartment. Police say he met his alleged killer on Craigslist.
Anyone surfing for sex assumes a certain amount of risk and personal responsibility, and Craigslist managers post plenty of warnings about scams and safety.
But the website also has a responsibility to enforce its own rules and curb offers for prostitution and pornography.
Whether someone is looking for Mr. Right, or Mr. Right Now, online personals should be monitored by the site and approached with caution by the user.
That's a page from my notebook.