For educational purposes I am creating a fairly straightforward Drupal 6 site. I have created 2 sites with Drupal7 recently, but this is going to be a Drupal 6 learning environment.
Having set up the site manually, not using Fantastico or other script, the first thing to notice is that module installation is done via manual upload, something that Drupal 7 can handle via url or through tar.gz file upload. I am planning to implement the http://drupal.org/project/wysiwyg module and then extend the module in order to create a citation tag.
++ more to follow ++

Demonstrating Kaprekars routine.

6174 is a very special number, it looks pretty straightforward but try this.
Sort it by highest to lowest number : 7641
Reverse that number : 1467
Subtract them : 6174

That looks familiar.