ClickZ: Study: URL-Based E-Mail Blocking On The Rise

Many email users are now finding that their internet service providers are screening out emails that contain blacklisted web addresses. The filtering comes as an effort to fight spam. But unlike IP number blacklists that block certain sending computers, these URL blacklists seldom provide a mechanism for correcting a URL that gets improperly included. Marketers using "spammy" email lists or even having their URLs included among lists of blacklisted ones may find their web addresses blocked.