What is a tag, and how do choose which ones to use when asking a question?

tags are keywords that aid the members in finding the answers to your questions. for example, your tags refer to tags themselves, iq as a site, and frequently asked questions. this may lead me to refer you to the FAQ link on the left of the page and look for "tags" there. (see?)

tags need to be relevant to the subject matter of the question, otherwise they could be completely misleading. tags that are seemingly out of place or spelled incorrectly are subject to change, as and when the mods notice them.

I always try to put 4 tags to a question and relate them to a question. It really bugs me when someone asks a question like..

where can I buy tea? and uses the tags "where,can,buy tea"

I've seen tags on questions like "why, Me" in one case I even saw the tag "question" all of which are very unhelpful for the growth of the site of finding questions.

Just think of Google - what keywords would someone have to type in to find your question? Simple as that :-) If they were going to search for your question, they would not get any decent results if they put the tag word " what" in lol. They might however put the word "tag" in and would certainly find your question at the top of the list that results. In your particular case, there aren't that many tag words that can be associated with this particular question.