Sometimes I'll upvote things, especially icon set which I don't have a need for right that second, as an ad-hoc bookmark so I can find it later under my "saved stories".
And this is why a "save story" feature should be added. I do this too and it's probably breaking the logic behind why upvote exists in the first place.
But isn't saving a story the ultimate form of upvote flattering? I'd also vote for it's existence, if only to be worth more than a mere upvote.