I would think that these ads aren't exactly to-the-point considering what is offered is extremely illegal. I sincerely doubt you could reliably identify them based on keywords alone.
If it were so easy to spot child exploitation ads, why doesn't the police or the FBI monitor sites like Craigslist? I'd much rather see the people involved in that filthy business prosecuted than simply having their ads blocked (which doesn't do anything for the victims).
