On Ter, 15 Mai 2012, Joseph Tam wrote:
It works by placing innocuous individualized tags in HTML formatted Email e.g. "<img src="http://your.domain/?id={hash}>" that downloads a 1x1 dot). You can then correlate web logs with the hashes to see which messages got rendered. A hit does not necessarily mean it got read, and the absense does not mean it was ignored, but it's better than nothing. If you value your privacy, turn off HTML rendering on your Email reader.
Even with HTML on, many (if not most) readers, including webmail ones,
disable loading remote images to avoid the problem, unless the users
specifically asks the images to be loaded.
-- Spock: We suffered 23 casualties in that attack, Captain.
Eduardo M KALINOWSKI eduardo@kalinowski.com.br