I've been thinking about this too, particularly regarding the (quite a lot of) tinyfics for rare pairings/canons that I've written for memes and challenges, and which languish in individual LJ comments where no one who wants them will ever find them. Do they go on AO3, on a fandom archive comm, or do I start maintaining a personal masterlist, or what? Do I post even the mediocre ones on rarity grounds, or let them lie in the dark forever? :/