[northwest]

Same here. This is definitely not ok.

EDIT 1: I also checked "Clear history when Firefox closes" and included "Cache" in the definition of "history". And the tracking is still happening. So either the site uses another tracking method in addition to the etag method or there is a big f#ck-up in FF.

EDIT 2: The tracking even continues when I check "Always use private browsing mode" and then close the browser and open it again.

EDIT 3: Even a complete removal and a clean install of FF (without any add-ons which may interfere) lets the tacking happen, for both the case of "EDIT 1" and "EDIT 2".

So this pretty certainly seems to be a bug.

[kfcm]

The only way I've found to ensure this doesn't happen is to set about:config -> network.http.use_cache = false.

Private browsing keeps it for at least one restart (with clear everything set in options), even though I can't see tracker.jpg in about:cache anywhere. Other weird thing is tracker.jpg isn't showing up in a filesystem search anywhere. Wondering if there's something stored in the sqllite files.

[northwest]

That works, thanks!

[northwest]

EDIT 4: Even having set about:config -> browser.cache.disk.enable -> false, I have to close/open the browser twice in order for the cache (and tracking) to disappear.