[eluser]Pascal Kriete[/eluser]
Ignacio, it's not a joke.
Though stalled, there have been ongoing plans to convert it to CodeIgniter.
Joomla is quickly set up, the system works, and it's the only active site of it's kind. So regardless of how it was built, it's a useful resource that would not have been up as early as it was - had it been built on CI.
This website runs on ExpressionEngine, not CodeIgniter. SImply because it makes more sense that way.
Use what's right for the job.
Cheers,
Pascal