In small online communities, I feel it's safer to allow people to over-vote than to under-vote.
I feel that if I am directed to a small site or blog which has some sort of "I liked this" voting mechanism I am doing them and their community the great service of taking a second of my time to give back to them (after having spent minutes reading or watching the proffered content and giving them advert revenues). Please, let me give you some money.
However, most-if-not-all sites essentially scold me. That is, they make me sign up (ugh) in order to further their site and its content -- they make me go through an unnecessary and tedious process (which I will probably regret later when I keep receiving emails from them) in order for ME to give THEM MY VALUABLE DATA. (If you don't think that data is valuable well, then ... dot dot dot).
Instead, we as web developers should be BEGGING for people's input at every opportunity we can get -- kind of like those "Who's butt is this? J-Lo's? Brad Pitt's?" flashing adverts.
And for all of you right-wing DB Admins: yes, I agree: it's a horrible suggestion: a row without a userid; however, Machine Learners would argue that userid or not, it's still valuable data and we shouldn't limit our inputs only to the "elite" (who have already signed up) or the "gullible" (who will agree to sign up so they can give us money).
The next time you are going to use some web-two-oh popup modal to require a guest (notice the difference between "customer" or "page hit") to "Login or Signup", think about what the USER is giving back to YOUR SITE and decide if it's really necessary.
In my opinion, until you get to the scale that digg.com was 3 years ago and the impact that voting makes on their site, don't assume that someone is trying to game your system -- or that it matters even if they are.
Hell, Codding Horror can use the same captcha and get away with it.
