What does the "margin of error" mean?

A good place to start is with the following three posts on the random variation inherent in all sample surveys and what a consumer can do to minimize it (each post has a link at the end connecting to the next post in the series):
Divergent Polls
More Divergent Than They Should Be?
So What Should a Junkie Do?

Also, click on this link to display short excerpts of all of the posts concerning sampling error in reverse chronological order (most recent first).

Related Entries - FAQ, Sampling Error