[pweissbrod]

Theyre similar to Perl in the sense that theyre extremely powerful and flexible but they tend to be highly customized to the business domain of their design.

This type of languages enable a very small team of engineers to be profoundly productive but the learning curve with adopting an existing project can be quite high even for expert programmers due to the lack of consistent patterns you would expect for more Enterprise languages like Java .net or python.

The end result is great success for small smart teams but lack of interchangeability and scalability for Enterprises

Edit: I once wrote a closure web application for a volunteer project. The experience was wonderful and painless however finding Developers to a system maintain the code base remains a serious challenge today

[dman]

As an industry we dont take maintainability very seriously. You think it would be easy to maintain web apps written in more "mainstream" languages from a couple of years ago?

[MaxBarraclough]

The web industry constantly chases fads, sure, but that's not true of the whole software world.