What was so special about December ’05 and April ’06?

Have a look at this chart of Alexa rankings of Digg and Del.icio.us. Both of them– and a lot of other collaborative-media sites like Technorati, Reddit, and MetaFilter— have small spikes in late 2005 and a giant spike right in the middle of April 2006. What happened? What were they doing, what was the world doing, that made those sites so popular so quickly?

Looking at one site you’d think that there were a couple of points where a critical mass built up, or maybe they scooped a couple good stories, or got some very positive coverage in a few major venues. Or perhaps they released a new version of their software and got a lot easier to use and therefore more popular.

But seeing all those sites with the same traffic patterns makes me think that it was something about the zeitgeist that made all those buzzwords like “collaborative news” and “citizen media” relevant to a lot more citizens.

Obviously, I want that kind of relevance, that kind of traffic and success, for StyleFeeder.

To get that, I have to find out not only what made it happen then, but what can make it happen now. Neither answer is clear.