I have a question... is it possible to do a truely anonymous poll? That is, can people answer as anon or do you have to be signed in to answer a poll as I think that might affect the number of "I didn't like it's" a fic might get? Do you always set up your polls with the answers viewable to all?

Yes. I don't think it ever occurred to me not to. As I said to etoile_dunord below, I tend to check out the comments first to see what sort of response the fic has already gotten as a way of gauging whether or not I might like it, and if I see the names of people I know there, then their opinion factors in more heavily. But it might be worth a shot to switch it up, and see if there's a marked difference in poll response.

Does everyone who ticked liked it also tick read it?

No, and this is something that gets pointed out by readers from time to time. I think people just click "liked it" or the goofy option without thinking to click "read it" most of the time, because their having read the fic would be implied. I think perhaps I'll start rephrasing the options on your suggestion and we'll see how it turns out!