jQuery Pluginization (see comment for slide order)

jquery-pluginization.js

function longUrl( elem ) {
  var href = elem.attr( 'href' ),
    api = 'http://www.longurlplease.com/api/v1.1?callback=?';
  
  // Fetch JSON data.
  jQuery.getJSON( api, { q: href }, function(data){
    if ( data[ href ] ) {
      // Update the element's title attribute.
      elem.attr( 'title', data[ href ] );
    }
  });
};

Here are the general steps, in-order:

1. Generic non-jQuery style code
2. The basic jQuery plugin
3. AJAX request caching
4. Using a closure
5. Global optional callback
6. Optional attribute argument
7. Optional lengthen argument
8. Reworking the optional lengthen argument
9. A single, optional options argument
10. With global defaults
11. Making things more generalized
12. Making things too generalized?