In his presentation at OSCON, Roger Magoulas, the director of O’Reilly Research, provided some interesting graphs based on our trends data mart. Here’s the 3-year programming language market share trend based on computer book sales:
I wrote yesterday about the rise of Ruby and Javascript, driven by the move towards Web 2.0 applications. Also worthy of note in these graphs is the long, slow decline of Java and C/C++, and the continuing rise in market share of C#. You can see how Ruby’s sharp ascent follows the introduction of Rails, and that PHP’s fortunes reversed before book sales showed that web developers in search of rapid development languages moved over to RoR (and Microsoft’s ASP.Net suite of technologies.)
Also worth noting on this chart is that book sales tend to spike even before the release of commercial languages, as the vendors work with publishers to get books out by the release date, while books on open source projects tend to trail the release date. On the one hand, you could interpret this as meaning that open source is slower to market, but I think it says the opposite: open source projects can move fast, and catch publishers by surprise. Few publishers expected the quick uptake of Java AJAX and Ruby on Rails.