Is this still useful? I thought GMail switched to server-side opening the images and caching them (for multiple users if the URL is the same).
This destroyed the tracking methods mail-based advertising used, and since this is a market that competes with Google’s web-based advertising business, many mail advertising companies cried outrage and abuse of power.
So with this change in effect, why would be need an extension like this?
The URLs are different per-user, so that wasn’t going to be any help.
There were a lot of high hopes from privacy advocates (and fears from marketers) last December that GMail’s new image caching was going to fetch all images on email delivery. This would make open tracking impossible. Unhappily or happily (depending on whether you are a human or track them like cattle), very little has changed. Tracking unique opens has even improved, but now marketers don’t get the user’s IP address.
I thought Google requested every image, regardless of wether the email was read or not, to negate the tracking.
It is. Essentially the server-side proxying that gmail now does only makes the location/device tracking irrelevant. Tracking images still effectively detect opens even going through the proxy.