Inspired by a map for Clojure, I created a map for Tapestry users:
View Apache Tapestry Users Worldwide in a larger map
Want to add yourself? The map is wide open, something I'll probably regret later.
Update: People have been adding themselves over the weekend, and trends are starting to appear. It seems like adoption is heavier in Europe than in the US (at least, among the narrow set of people who use Tapestry, know about the map, and have actually added themselves). Still, if that sample is true, it begs the question: why? Is it more to do with the European developers, or due to features of Tapestry (such as localization support).
I'm tending towards the former: talking with many Europeans shows that managers have a more "hands off" attitude towards project leaders, who are given more free reign to use tools of choice as long as they deliver. But that's also a horrible generalization from limited data. In fact, a contrary opinion was offered by some developers in Oslo last september ... in Norway, a small number of developers make strong vocal choices (lately, Spring and SpringMVC) and the whole community follows along. But even Europe is a big place which room for many different developer cultures.