Digg has suffered an alarming 50 percent drop in US traffic over the last six months according to information from Quantcast.

Updated below with statistics from Digg.

The data, which is based on estimates and not direct measurements, suggests that the once mighty bookmarking and social sharing service has seen monthly visits in the US drop from 9.4 million in May to 4.6 million in October.

digg us traffic 520x373 US Traffic to Digg Reportedly Down 50% Over Last 6 Months [Updated: Not True Says Digg]

Times have tougher for Digg since its founder Kevin Rose stepped down from his position as CEO in June 2010 after growing frustrating by the lack of production innovation and the stress of “keeping 90 people on the same page as to what’s going on in the company”.

While Rose moved on to focus on a number of startups he is involved — including newly launched Oink — the company he founded has struggled despite unveiling number of designs and content shifts with little sign of recreating its early success.

Digg, which was forced to lay-off off more than a third of its staff last October 2010, is placed considerable emphasis on covering breaking news with its most recent feature, Newsroom, designed to “separate the news from the noise”.

In contrast to Digg, rival Reddit is going from strength to strength having served 1.8 billion page views to 28 million unique visitors during October, although these stats cover worldwide users and not the US.

Quantcast’s estimate for Reddit shows varying levels of traffic in the last six month with a peak of 15 million US visitors registered during June. The most recent measurement estimates that the site saw 13.7 million US visitors during October — that’s almost three times more than Digg — which puts US visits at around half of its total traffic.

reddit us traffic 520x370 US Traffic to Digg Reportedly Down 50% Over Last 6 Months [Updated: Not True Says Digg]

With a range of new features for Google+ making it all the more competitive, and importantly closer aligned with Google products, competition with Facebook, Twitter and other social media has never been fiercer for social sharing services like Digg and Reddit.

Update: the Quantcast chart is “wrong” according to Digg which has published a blog post with the actual traffic figures from the site. The conclusion is “pretty different if you’re looking at the actual data” rather than estimates, according to Digg’s Ben Folk-Williams.

The chart below shows a steady line of worldwide traffic, with visits from US consistently reported to account for half of the total.

diggtraffic 520x134 US Traffic to Digg Reportedly Down 50% Over Last 6 Months [Updated: Not True Says Digg]

Digg has also provided additional statistics too:

  • Digg Newsrooms have been in beta for a month and we are seeing great response – In particular page views per visit are up 3x versus classic Digg.
  • We’re seeing dramatically higher engagement from our Facebook fans, with users coming from Facebook spending an average of 15 minutes on site as compared to 10 minutes for other logged in users.
  • On mobile, we’ve seen a 23% increase in daily users since the launch of our revised iOS app with Newsroom integration.
  • 51% of our traffic is direct. That metric can be a tricky one to measure correctly if you aren’t careful – we are. That means 13 million times every month someone types Digg.com into a browser.