APEWS is very aggressive (meaning its use as a spam filter drives a lot of false positive blocking) and as measured by me on August 11, 2007, lists approximately 42% of the Internet. (By “the Internet” I mean IP4 address space.) In other words, they list nearly half the Earth, suggesting that anybody who actually wants to receive mail probably cannot use APEWS as a spam filter. This strongly suggests that very few people are going to block your mail because of the APEWS listing.