TDF... it's just a vicious cycle of traffic. That webmaster could have given a very high ratio to one of his other trades, causing his script to favor that site and draw hits away from other trades, or he could be forcing too many hits to too many sites ( a common ailment with guys who don't know how to manage their trades). A lot of guys will set more forces than they have traffic coming in, and the script can never keep up with them all, so some trades fall behind quickly or just die off.
Or he could just be a polesmoker, and stopped returning, hoping that the hits you are forcing will beef up his other trades before you notice and remove his site from your script.
