I've just release my first Wordpress plugin - External links nofollow, open in new tab, favicon. It was an interesting process getting to this point. The plugin is focused on improving external links - with the initial round of features being a) controlling nofollow/dofollow on a per-domain basis, b) adding icons so visitors know they're seeing an external link, c) causing clicks on the link to open into a new tab. I started on this plugin thinking solely about the nofollow/dofollow support, since none of the existing plugins did it the way I wanted it done. But as I reviewed other plugins including Drupal modules these other features made sense as well.
I've got some ideas for further features including
- Rewriting urls to add affiliate codes for certain outbound URL's
- Outbound click tracking
- Add a warning page saying "You are about to visit _____ "
To make suggestions either go to the plugin page on wordpress.org, or the Issues page on the Github repository https://github.com/robogeek/wp-nofollow/issues