Something that irks me:
When someone on a forum, keyboard-related or otherwise, asks a question or creates a poll to the effect of, "Which is better, X or Y?", and people vote even though they know nothing about one of the two options.
Now it's quite easy to see why this habit would mess up the results...
For example, if there's X and Y, and X is a product that is popular and well-liked, and Y is a product that is even better than X, but only a handful of people have ever heard of it, the votes/recommendations for X over Y will create the impression that Y is inferior to X, even if everyone who has actually tried both agrees that Y is superior.
Even worse, this effect can create a feedback loop. Let's keep X as the established product, and say that Y is something completely new but better. Someone discovers Y, asks, "Which is better, X or Y?" Everyone votes for X even though they know nothing about Y. So the discoverer gets X instead of Y, and then when the next guy asks the same question, there's still nobody to support Y. And so on.
Grr...
