When you get an e mail and you click on the 'Report spam' icon, it disappears from you, but does anything actually ever get done to chase up the spammers or anything, or is it just a waste of time and you should just delete it?
I don't know; but the effectiveness of email depends on blocking spammers, so I imagine they do have people, or at least robots, who will block the sender in future if it's reported.
depends. I had an email account that wasn't protected from spam for a while and it just used to flood in - 100 or more a day. My hotmail account, which is protected, gets one or two at the very most. On the other hand I have a friend whose hotmail account gets 5-10 a day. So I think identifying spam does make a difference but it's hard to say how much.