22% of permission-based e-mail was blocked by ISPs in 2004

22% of permission-based e-mail was blocked by top ISPs in 2004, up 3.3% from the second half of 2003, according to Return Path. Road Runner blocked the most permission-based e-mails at 35%, Mail.com blocked 34% and Comcast blocked 31%. EarthLink blocked the fewest at only 5%, while primary ISPs Yahoo and MSN blocked 11% and 10%, respectively.