> But that of course also means that now the URL on the history stack for this particular view will always have the filter in it (as opposed to an initial visit without having touched anything).

I would have one state for when the user first entered the page, and then the first time they modify a filter, add a 2nd state. From thereon, keep updating/replacing that state.

This way if the user clicks into the page, and modifies a dozen things they can

1. Refresh and keep all their filters, or share with a friend 2. Press back to basically clear all their filters (get back to the initial state of the page) 3. Only 1 more press of back to get back to where-ever they came from