I wanted to know your opinions about having Silverlight installed. Also, I don't remember installing this. Is it necessary? Is this an app? or an "add on"? Does it have the potential to negatively impact my Computer? In light of the recent scare on third party "apps"..is this safe? One last thing, should I leave the on off switch for "third party developers" on the "extensions" tab in Safari preferences in the off or on position?