And who's behind an ad trolling for dirt on the dead cabbie? Last week's edition of Gay Chicago ran something creepy. It was an ad that began "Help Us Fight Cab Violence! Have you had a memorable, unusual or bad experience with a cab driver?" If you had, there was a number to call and a Web site to visit. In passing, the ad mentioned that on February 4 an "unfortunate incident happened between a cab driver and a Lakeview resident." The ad didn't say what, though presumably it was a choice example of abusiveness. The Web site, endcabviolence.com, revealed...