The new Yahoo Buzz feature is quickly becoming the new test of web site scalability, generating massive waves of visitors that can dwarf the volume of traffic produced by a link on the front pages of Slashdot or Digg. Those two sites have been the historic benchmarks for sudden waves of traffic that can overwhelm web servers (see Slashdot Effect for background).
But Yahoo Buzz, a Digg-style social news site, has added a new wrinkle that cranks the traffic volume up to 11: the top Buzz stories are linked from the Yahoo home page, creating a traffic tsunami. News sites that have participated in the Yahoo Buzz beta are reporting unprecedented traffic spikes. Most of these early recipients of these "Buzz Effect" surges have been established sites that have managed the sudden traffic hit. This week we've started to see examples of the way a Buzz link on the Yahoo front page can crush a smaller site. As Buzz begins to include more news sources, it seems likely to raise the bar for web scalability for many blogs and news sites.
First, let's look at some of the data from early Buzz publishers:
- The Huffington Post reported 800,000 unique visitors from a Yahoo-linked story.
- A link from Buzz helped Salon record more than 1 million visits in a day for the first time ever.
- A Buzz link gave TechCrunch its heaviest traffic day ever, despite the fact that it appeared on a Saturday.
- Sugar, Inc. sites received 1.8 million unique visitors sent from five different Buzz stories on the Yahoo home page.
But what happens when that kind of traffic hits a site accustomed to more modest traffic? FaceStat was averaging about 20,000 page views a day for its site, where users evaluate head shots uploaded by other users. The site was featured on Yahoo Buzz and linked from the Yahoo home page on a Sunday. The pageviews soared to nearly 700,000 on June 1, knocking the site offline. FaceStat's Brendan O'Connor and Lukas Biewald provide accounts of how they frantically re-architected the site to get it working again. Biewald writes:
After working so hard to get users to come to your site, it's amazingly frustrating to see hundreds of thousands of people suddenly locked out. Unbelievably, our webserver (nginx) couldn't even reliably show that static page