Most people think of emails when hearing "spam" or "UCE". But, didn't you notice all the crap when searching the web for someting - I mean all the link-farms which lead you to ebay or these sites.
What do you think about "Spam"-filters for the web? I don't mean censorship like in China, although the principle is the same - just what if you had your own personal filter (like a personal firewall) which you could train and which would mark every "unwanted" page as such so you can separate the wheat from the chaff at once?