Slash Dot /.

``Earlier today we published an analysis of the top traffic drivers in social media, based on data from Web analytics company Woopra. The biggest traffic driver was StumbleUpon (51%), followed by Digg (30%), Hacker News (12%) and Reddit (5%). Surprisingly, tech news community Slashdot was  in the list of top referrers. In fact, according to Woopra CEO John Pozadzides, Slashdot "drives close to 0% of traffic to the sites Woopra measures." (emphasis ours)''

From NYT.

I should use more StumbleUpon.