it would be useful to me if Adblock Plus could optionally save the last site/url which triggered a rule. Sometimes I create generic filter rules which I later want to propose for inclusion in EasyList. Problem is that I can't always find an exemplary site which demonstrates both the ad as well as the how the filter blocks it. This, of course, can be achieved by using the time a rule was last triggered and Firefox' history but I wouldn't mind a slightly more comfortable way, especially if it would be easy to add to ABP.
I considered this several times already - but this has privacy implications. Some people are already concerned that Adblock Plus saves number of filter hits and this isn't cleared together with private data, here we would be storing visited URLs which would be really concerning.
I have no idea how the hit counter is currently implemented in ABP, but at the top of my head I'm thinking that an opt-in scheme should appease people who have justified privacy concerns as long as no privacy related data is created.