fair enough, but I still question why a tutorial needs to be rewritten to make use of a different CSS framework. Are there that many people forking this tutorial that they want something cleaner to work with? I just don't get it.

The full "rewrite" took less than two weeks, and much of that was redoing screenshots and mockups (easy, dull work).

The motivation for the change was to please readers. Happy readers make for a happy author. Among other things, happy readers buy ebooks and screencasts. For a free online book, the Rails Tutorial makes a surprising amount of money. I'd like to keep that record going with the 2nd edition.

I think I misunderstood this whole thing! The tutorial was rewritten to make use of bootstrap instead of blueprint. Not the rails tutorial site was rewritten to be designed using bootstrap. It all makes sense now.

I think the term re-written is a bit over-the-top. I've gone through to chapter 10 of the tutorial, and the focus is largely on rails/ruby.

Blueprint did not factor a great deal in the original version and, honestly, Bootstrap is probably more relevant at this point.