What's okay on Facebook? On sites like MySpace, anything goes (or seems to), but the rules of etiquette on Facebook seem to be a little more refined--not a lot, mind you, but a little. Keep these tips in mind, whether you're making your first friend or your 1000th.
http://www.pcworld.com/article/169120/facebook_etiquette_10_rules_for_better_socializing.html