How do I "vote" on the questions and answers?

Yes, every person here can vote on the questions and answers. To the left of a Question or Answer, you will see a number which represents the vote. There is a plus sign above and a minus sign below. Just click on the plus sign to show you think the Question is interesting or the Answer is helpful. You can also click on the minus sign if you think the Q or A isn't good or is misleading, hasn't really answered the Q, etc. It's very simple

One last thing, if you've posed a question and one of the responses really answered your question, then not only can you vote it, but you can "accept" the response as your answer by clicking on the checkmark next to that answer.