The following data compares traffic from Digg and Stumble Upon using Google Analytics. The first website was on the front page of Digg, while the second website was on buzz section of Stumble Upon. Both articles were YouTube videos with very little content.
The article was called Top 10 Useless USB Gadgets. It was merely a Youtube video embedded on www.scubasewj.com (blog).
It made the front page of digg around noon and drove about 4700 visitors in 1 hour. The amount of visitors dropped drastically after the first hour. The average pageviews were only 1.15 and time spend was approximately 2 minutes. At the end of the day digg brought 32 new RSS subscribers (data not shown).
The article was called How Italians Tell Time, it too was a Youtube video, embedded on this very blog.It made the buzz page for the humor section of Stumble Upon late night on 12-7-06. It drove about 4100 visitors in a 5 day period. Average pageviews were 1.55 and the time spent was about the same as the article on digg, 2 minutes. At the end of the first day RSS subscribers increased by 50 and continued to increase throughout the days. It peaked at 403 RSS subscribers.
Digg brought a ton of traffic but it was very short living and with most of the visitors looking at only one page. While Stumble Upon brought ton of traffic but spread out throughout a few days and more visitors looked at more than one page. Stumble also increased subscribers by a great deal.
This is information to keep in mind before using Digg or Stumble Upon to drive traffic to your website.