I'm curious about why people would risk buying links and how they go about making sure that the links they've paid for can't be identified by Google.

I've seen a bunch of WTB or WTS links threads on various forums but it must be quite hard to sort out the good prospects from the bad and the liars. Does anyone have experience of buying links? Did it work? Have you had any get devalued? How did you agree prices, what's the most common way to get ripped off?

It seems like it coud be a very expensive and risky way to try to improve rankings.