Hey, why not add commenting to the wordpress plugin and theme databases (http://wordpress.org/extend/)?
This will help everyone in many ways:
- People can ask questions about the plugin/theme right here instead of visiting the author's page and finding out how to contact the author in the first place.
- Greatly helps authors who would prefer a centralized managed platform to address the FAQ and problems arising from their plugins or themes.
- People could read the comments and know how good the plugin or theme is for them before they actually try it. Saves time.
And besides, this is not much of an asking; the web has evolved, hasn't it?