The offending ads are gone from my site and other groups I belong to. In fact, yahoo promised the moderator of another Ukrainian list similarly saddled with those ads that not only are they removing the ads from our respective sites, but from all of yahoo groups entirely.
The moral of this story is that everyone can do something to stop this scourge, however little. As they say, every little bit helps.
Someone said that evil happens when good men (and women) do nothing. So while we can't stop the traffickers, or even block a lot of internet traffic, we can stop them from trying to legitimize their so-called "trade" by insinuating themselves amongst decent folk and masquerading as innocuous "dating and escort services."
We can do it simply by deciding not to turn a blind eye to such attempts, and doing whatever we can to re-stigmatize sleaze. By and large, horny young (and old) guys prowling for porn and prostitutes don't think much about the the women they're screwing, or viewing ... much less whether or not they are trafficked. But regardless of whether or not they care, they need to be made aware that someone does.
This little victory is, of course, just a drop in the bucket. But if, as the Ukrainian saying goes, a drop of kerosene can spoil a barrel of honey, I imagine the reverse can be true as well.
So maybe a congratulatory note of thanks to yahoo would be in order.