Because it's easy to learn, has good community support, and powerful metaprogramming features. In a nutshell it's easy to think and create in ruby. Also signif

Because it's easy to learn, has good community support, and powerful metaprogramming features. In a nutshell it's easy to think and create in ruby. Also significant is that the tradeoffs you must live with (speed, lousy debugging/refactoring tools) to get ruby's benefits just don't matter for a huge swath of web projects. Ruby is optimized for a very common, very pragmatic set of problems.