18. Digg - Social Content Sharing Bring New Site Visitors As a content developer you have 2 chances to impress - the headline and the content, users generally more negative (SU gives just website), more diversity in algorithm, users don’t spend a lot of time surfing - read or post and are gone.
19. Way more addictive/interactive, provides traffic that is more consistent, more likely to click links and will return more often, broader and more diverse audience. StumbleUpon - Community Surfing Bring New Site Visitors