Gmail changes: Now possible to track almost every email
Since gmail changed that images are displayed by default (old accounts are asked if they want to enable this feature) most of the gmail accounts can be tracked when the email was read 
Simply include image with unique URL (easiest is to add unique parameter) and when the image is loaded by google server user opened the email.
Quite useful to filter the useful emails from junk
Simply include image with unique URL (easiest is to add unique parameter) and when the image is loaded by google server user opened the email.
Quite useful to filter the useful emails from junk
Code:
news.techworld.com/security/3493810/marketers-excited-about-gmail-image-display-changes/
