I wrote a emailing process in PHP that sends out emails (via my webhost's smtp) to a list that the same script harvests from websites. After sending out 300 scraped emails, my website tracker notice only 1 visitor coming from aol mail. Theres lots of custom domains and gmails and couple of yahoo mails in the email blast list. To see if the email is hitting the spam filters, I send some of the emails to my own gmails and they inboxed nicely. Could it be that not enough emails are sent to see some hits from it? Or somehow gmail is tricking me into thinking that my emails are inboxing (at least when sent to @gmail.com addresses)?