According to this new post to the CodeIgniter blog, they've added a new feature to their Wiki - a link between them and the CodeIgniter forums.

Threads will be automatically created and linked for you via the discussion links found at the bottom of wiki articles. More details about this integration can be found at a blog post made in the ExpressionEngine blog, as well as a free ExpressionEngine extension to implement this on your own sites that utilize the ExpressionEngine wiki and discussion forum.

The plugin (the "Wiki Forum Talk" extension) bridges the two components and either makes a new topic when a new wiki entry is added or, if there's already a forum topic for the entry, it automatically links to it.