I would recommend checking out this site fist.
http://www.bitlaw.com/copyright/fair_use.html
there are a lot of people that don't want to accept fair use so I would recommend learn as much as you can about it and make sure your post falls under it. also be prepared to supply information on why your post if fair use if it does get flagged. there will even be some people that will try to tell you that fair use doesn't matter. best thing to do is supply information and some people no matter how much you prove you have the legal right to use fair use will still be agienst it. luckly we have the www to search now days. xD
sorry im not more helpful.