It reports it as something that should not be on the site. But there won't be an effect without several people flagging the comment, so accidentally flagging a comment once won't do anything.
(And for the sake of sanity: If you want something gone fast and efficiently, it is easier to report it to a moderator. For regular two word spam, the flag is alright, unless the person that wrote it continues, then you might need to notify a moderator).
On another note, please do no write titles in all caps, it is annoying, and we don't like to be yelled at.
No problem. Glad to help. And yeah, the all caps thing is just like how we don't want all caps posts or comments, or all bold, all italic and so on. It is a bit annoying to look at, and the caps makes it, well, look like you are yelling.