You have three options: liked, shrug, and dislike. It is generally advised that you vote this way:
Like anything that you enjoy drinking. If you saw this beer available somewhere, and you would seriously consider ordering it, vote like.
Shrug anything you're indifferent about. If you would only consider ordering this beer if it were the only thing on the menu that you didn't dislike, it's probably a shrug.
Dislike anything you'd rather not drink. If you wouldn't order this beer even if it were the only thing on the menu, vote dislike.
Additional voting tips:
Don't vote on things you haven't tried - you may cut yourself off from good suggestions.
Shrugs don't affect your grouping. The shrug option is just a way to mark that you have tried a beer, but don't have strong feelings about it.
If you know that your tastes vary greatly depending on the situation, consider creating a second account to keep votes separate. Then, for example, you can like sweet stouts and dislike IPAs in your "dessert" account while you dislike sweet stouts and like IPAs in your "dinner" account.
You may also want to check out the notes on homebrew.
These numbers are your personal rating for each beer, and they are given on a ten-point scale. A rating of 5.0 means we're sure you'll like a beer, while -5.0 means we're sure you'll dislike a beer.
Ratings between the ends are fuzzier. A rating greater than 0.0 means we think you're more likely to like the beer than dislike it. A rating less than 0.0 means you'll likely dislike the beer. Exactly 0.0 means we're unsure - members in your group disagree about it.
A rating of "unr." means the beer hasn't been rated by anyone in your group. Go out and try it - you may bring valuable information to other members.
A beer with "unr." in the rating column indicates that BeerRiot doesn't know how to rate that beer for you. Either you haven't voted on enough beers for BeerRiot to get a feeling for you yet, or your tastes are drastically different than all of the other members. Try and vote on some more beers, or double check your previous votes.
The beer filters box lives just under the search box on the right side of the page. Each line shows or hides beers fitting the description of that line. For example, clicking the next to likes, and the next to dislikes will ensure that any beer list you look at will include beers that you have liked, but exclude beers that you have disliked.
Why don't I see any beers?
If you're not seeing any beers on these pages, it probably means that your filters are set too tightly. Look at the filter list just under the search box in the upper right. Each highlighted is hiding some beers in your lists. Flip a few of them to the to show those beers instead.
Why does a beer that I have disliked show up with a positive score?
It could be a number of things. If you're new to BeerRiot, it probably just means we don't know enough about your tastes yet.
If you've been here a while, it just means a majority of your group disagrees with you. It may be that the last time you had the beer, it was paired with the wrong food, or came from a bad tap. You may want to consider trying it again under different circumstances.
If it really bothers you, just hide the beers you have disliked by clicking the next to the "dislikes" line in the beer filter under the search box in the upper right. BeerRiot will hide all of the beers you have disliked in your lists and replace them with something better.