MSGTAG - I Did Not Tag... Get It

As an astute read of About Email, your perpetual quest to know everything (even if that might be just a bit; who knows?) has taught you that the new springs from something that is now old in hindsight. Of course, the tagging of blogs, posts, images and what not is yesterday's news to you. While these tags are used to categorize and find information with the help of metadata, at least in theory, the MSGTAGging of emails has a different purpose, but it, too, can be abused:
›› MSGTAG provides an easy to use and convenient way to be notified when the recipient of an email you sent has opened it. (Windows)