I run a network of outdoor sites and this guy spammed everyone of my sites with link exchange requests. See what most people don't know is all the 40 sites have the "admin" contact for abuse email link in them. This means he is harvesting emails and hiding behind link exchange request to spam.
When I told him this he flew off the handle until I notified him that I've been on the net 15 years and there is not much people can do these days that does not get past me. He again went into an email rant.
Three weeks later I started to get email link spam again, I finally had enough and proved to him the only reason why his site is on the Internet is because "I" allow it... never got a spam or email again.