well i dont think many site owners are going to trade links with a spam message , most site owners would only trade links with a person
with that being said , i do see emails trying to do that all the time..
Theres this one that always gets me , its like WARNING your link will be removed , then it goes on to explain its like a reverse listing , they give you a free link then email you and try to get a recip from you , if you dont they remove you.. good idea , but i never actually used it so ..