32 Rack Resources to Get You Started | Jason Seifer

What the heck is Rack and why is it getting so much press lately? Well, from it’s tag-line: “Rack provides an minimal interface between webservers supporting Ruby and Ruby frameworks.”

But what does that mean? Prior to Rack if you wanted to interface with Mongrel or Thin you had to write your own custom wrapper for talking to that web server. Rack standardized the interface for doing that and even added some icing on the cake.
(Link: 32 Rack Resources to Get You Started | Jason Seifer)