mass url aliasing and blog

This is from the help section of path.module:

Mass URL aliasing
Drupal also comes with user defined mass URL aliasing capabilities. You might like to see completely different URLs used by Drupal, or even URLs translated to the visitors' native language, in which case this feature is handy. Only an administrator with access to the website source code can set up this kind of aliases. You can define a conf_url_rewrite function in conf.php, following this example:

function conf_url_rewrite($path, $mode = 'incoming') {
  if ($mode == 'incoming') { // URL coming from a client
    return preg_replace('!^display/(\d+)$!', 'node/view/\1', $path);
  }
  else { // URL going out to a client
    $aliased = preg_replace('!^node/view/(\d+)$!', 'display/\1', $path);
    if ($aliased != $path) { return $aliased; }
  }
}

This function will shorten every node/view/$node_id type of URL to display/$node_id. Individual URL aliases defined on the browser interface of Drupal take precedence, so if you have the 'contact' page alias from the example above, then the display/3 alias will not be effective when outgoing links are created. Incoming URLs however always work with the mass URL aliased variant. Only the 'incoming' and 'outgoing' modes are supposed to be supported by your conf_url_rewrite function.

You cannot only use this feature to shorten the URLs, or to translate them to you own language, but also to add completely new subURLs to an already existing module's URL space, or to compose a bunch of existing stuff together to a common URL space. You can create a news section for example aliasing nodes and taxonomy overview pages falling under a 'news' vocabulary, thus having news/15 and news/sections/3 instead of node/view/15 and taxonomy/view/or/3. You need extensive knowledge of Drupal's inner workings and regular expressions though to make such advanced aliases.

KC