The user forums at http://www.codeigniter.com/forums/, offer a lively discussion of most CI issues on a regular basis. Comments and suggestions made are not always helpful (or accurate), but there are a number of "senior members", who usually make sense. It's a kind forum where people ask very obvious "newbie" questions, and get patient and helpful replies. But there's much more in the CI forums than just questions and answers—news, job boards, a place to request features, bug reports, and so on. Going through the forum from time to time can make us stay inline with the CI community and let us know what is being cooked.
The Wiki, at http://www.codeigniter.com/wiki/, is a repository for tips, tricks, hacks, plugins, and enhancements. It contains a lot of useful code, though coverage is not systematic.
If you are very curious to know what is going on, you can take a look at the SVN on http://dev.ellislab.com/svn/CodeIgniter/trunk/; you can download...