faceboook doesnt have fine grained filtering, you either hide a person completely, or unfriend them, or put up with their junk posts. luckily theres a third party solutoin that does give you more filtering options: Facebook Purity FTW! http://www.fbpurity.com/

the "hide" option, as its name declares only hides the posts from that application, it doesnt stop that application from harvesting your facebook profile data, or from other people inviting you to add that application or notifications from that application. one solution is the facebook purity script available from http://bit.ly/fbpure which adds a "block app" function to each post from any application, which allows you to actually block the application with just a couple of quick clicks. blocking the application means you will no longer see posts from that app, it will not be able to harvest any data from your profile, you will not ever be invited to add that application, you will not receieve notifications from that application. it also automatically hides all application posts, transferring them to a separate section, and also includes a whitelisting capability to allow app posts from apps you want to see.