When you (or more usually, your loser roommate) hires a prostitute on Craigslist or other online website, and that prostitute steals something when he/she leaves.
The prostitute cannot be tracked down, thanks to the anonymity of the internet. You don't have a name, you don't know where they live, they are just gone. Anything can be ho-snagged, although small valuables that wont be missed until later are the most common: cellphones, netbooks, etc. However, if the john is into bondage, this allows the ho-snagger to take bigger ticket items: TVs, stereos, computers couches, etc.
The theft could occur afterwards as well, as the prostitute may just case the place during the initial business transaction.
"I used to have a nice stereo, but I went home to visit my folks last weekend and it got ho-snagged. I wish my dumbass roommate would stop hiring anonymous hookers from Craigslist!"