On Wed, Nov 18, 2009 at 4:30 AM, Angus Mann <angus@xxxxxxxxxxxxx> wrote: > 1. Is possible. Google the term web-bug. Be prepared that it will only work > if the recipient has a HTML enabled email reader AND allows downloading of > images. Be prepared also that every time the email (including forwarded > emails) are viewed your server gets a hit. Might equal alot of hits. Just > embed an image with a unique filename (tiny or invisible if you want) in the > email and make it's source your server. Then track requests for that image. > In various environments, I use G-mail's web service, Thunderbird and Groupwise, and all 3 disable images by default specifically to prevent exactly what you are suggesting. I suspect many other mail clients do the same, not to mention a lot of people use text-only e-mail clients that cannot display images. Most people I know don't want to be tracked like this, and if they find you are doing it they will simply remove themselves from your mailing list and/or direct the messages to the trash. Andrew -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php