The BBC added a few social bookmarking buttons to their website during August allowing users to easily submit BBC content to Digg, Facebook, Reddit, Delicious and StumbleUpon.
With such a large site adding social bookmarking buttons it would be surprising if it resulted in a major increase in traffic. After all the BBC has much more traffic than Digg in the first place.
Looking at the traffic data from Alexa it appears that the BBC has been in decline this year. Even if it had a story on the Digg homepage every day would that result in much additional traffic? Why is the BBC in decline?
Probably the most interesting way to look at the impact of the Digg buttons is to examine the number of links pointing to each post.
The chart below shows every BBC post from July to November and it is clear that the number of links to each post is increasing. This seems to be due to the Digg effect as most of the posts with lots of links were on the Digg front page.