Dynamic product comparisons?

(FYI: I have no idea what WP version yet…this is just an exploratory question which will decide whether we use WP)

I’ve been trying to locate whether a WP module/cart exists for allowing web users to dynamically compare products on-the-fly. I’ve seen dozens of build-it-yourself comparison tables (mostly for review sites) but these are all hard-coded and not user-specified match-ups.

Does such a plugin/module exist?

Thanks for any help.