I just posted this on the LiveUser mailinglist, but I think this piece of information might interest a much broader audience.
I just implemented anonymous login with a CAPTCHA inside the WebBuilder2 framework using the LiveUser Session.php auth container and Text_CAPTCHA.
Works like a charm!
Basically LiveUser will first check if the username exist in the database. If not it will check if provided password matches the CAPTCHA phrase in the session. The user will obviously not be mapped to a perm user id (though this would be possible as well by placeing the necessary mapping into the liveuser_perm_users table). Here is the configuration file:
The code to generate the CAPTCHA needs to be moved into the login module eventually but for now you can find it here.
The observant of you might have noticed that this blog is actually run ontop of the WebBuilder2. By adding this feature to the WB2 I am one step closer to adding comments to this blog. Stay tunes :-)