Starting today, Gmail has started caching embedded images in emails and delivering them via their own servers. That lets Google “safely” turn images on by default (no more “Display images below” button) and presumably speed things up a bit, since everything will be coming from their own infrastructure.
It also means no more direct hosting of embedded images by third parties, cutting marketers off from their preferred tracking method. This doesn’t close the door on trackers completely, but it alters the landscape in a big way.
Gotta hand it to Google. This is a brilliant bit of jujitsu. Speed up their service and thwart unwanted tracking in one swift move. It remains to be seen if Google will go for the full hat trick by selling the tracking data it’s now sitting on top of, effectively supplanting the third parties they just cut out of the picture.
Update: Turns out the picture is a little murkier than it first appeared, as the specific details of Google’s caching and proxy aren’t entirely clear. There’s a whole lot of reverse engineering going on, but some aspects of Gmail’s privacy may have actually gotten worse while others have improved.