Crowd-Sourced
StumbleUpon
StumbleUpon allows users to share and rate websites. With over 8 Million contributors users can view only those pages which match their interests. StumbleUpon challenges search engines in that it targets users preferences and interests to present relevant websites.
A news sharing site where users can upload, share, vote and comment on content.
Digg
Users submit news, video or images to the site. The community can then vote (digg) those submissions thereby collectively determining the value.