Starting the development of a third party plugin (module, theme, add-on, extension or whatever you'd like to call it) for any software application or framework is only recommended if there is not yet an existing plugin that offers the desired functionality. Therefore it is important that plugin repositories make it as easy as possible to browse their contents.

I compared the sorting capabilities of the plugin repositories of Drupal, Eclipse, Firefox, Winamp and Wordpress.

Some observations:

• Only half of the repositories offer sorting by name. This is not surprising because this sorting is only useful if you already know the name of the plugin you are looking for. And even then the repository's search function would be a better way to locate your plugin.
• Only the Drupal repository does not provide listings sorted by rating or popularity. This is unfortunate because it is always interesting to know what other members of the community downloaded and/or liked.
• Only the Firefox repository offers a feed for each sorting. Feeds are an easy way to keep users up-to-date about recent changes.
• Overall, the Firefox repository provides the most complete sorting capabilities. This aligns with Mozilla's prominent pushing of Firefox' customizability.

A couple of months ago Dries published the results of a survey amongst Drupal users about the skills they would like to invest in. Module development and theme development came out at the top of the list. I'm wondering whether all these users really need to develop new modules and themes. Maybe they just have trouble finding what they need because of the limitations of the current repository.