I worked at a startup (full of awesome people!) that, among other things, helped stock analysts track who was opening their publications (emails).
It wasn't just about finding out when or where someone was opening it. It was about finding out who was forwarding these emails. Because there was a cost to be on this mailing list- if you're forwarding the contents, you're effectively pirating that information (I wave my hands a bit as I say this because there's a loooot of interpretation there and you are welcome to disagree).
So if you send out your latest post to 500 (paying) customers, you could see- how many people read it? How many people came back and read it again later? And most importantly, how many different IP addresses were loading that tracking pixel? Oh, the tracking says the content I sent to John was opened by 1000 different people? Okay, John is off the list now.
What made it better was that a lot of the content was graphical. So the 'tracking pixel' was the content itself. Short of downloading and forwarding the image, you couldn't share it without there being a record.
The company wasn't what I wanted to do so I moved on pretty quickly- but it still strikes me how neat it all was.
Edit later: Oh right, the other thing- you could tell what company the person who opened it was at by the IP Address, some of the time! "Hey, I didn't send it to anyone at <Company>, why the $%&* are they reading it?"
It wasn't just about finding out when or where someone was opening it. It was about finding out who was forwarding these emails. Because there was a cost to be on this mailing list- if you're forwarding the contents, you're effectively pirating that information (I wave my hands a bit as I say this because there's a loooot of interpretation there and you are welcome to disagree).
So if you send out your latest post to 500 (paying) customers, you could see- how many people read it? How many people came back and read it again later? And most importantly, how many different IP addresses were loading that tracking pixel? Oh, the tracking says the content I sent to John was opened by 1000 different people? Okay, John is off the list now.
What made it better was that a lot of the content was graphical. So the 'tracking pixel' was the content itself. Short of downloading and forwarding the image, you couldn't share it without there being a record.
The company wasn't what I wanted to do so I moved on pretty quickly- but it still strikes me how neat it all was.
Edit later: Oh right, the other thing- you could tell what company the person who opened it was at by the IP Address, some of the time! "Hey, I didn't send it to anyone at <Company>, why the $%&* are they reading it?"