Does rails3 provide any hooks for dropping in pluggable, re-usable components?

Question

What efforts have been made in rails 3 to encourage code re-use? Is there anything akin to merb slices / engines built into the framework that would allow me to drop in a configurable component such as a 'blog' engine? If so, what is considered best practice?

Answer 1

On Russian dolls and mountable apps

One of the hottest new features in Rails 3 is the ability to embed a Rails application in another Rails application. This allows the development of components that range from user authentication to a fully featured forum.

See here for more

You can also use Rack with Rails.