Anyone out there understand Oracle Database licensing?

It seems (but not clear) that you need both Server licenses and Named User licences. There is a minimum # of named user licenses of 5/processor for the standard edition. I'm trying to figure out whether I need any more than this for a web site. There will be no authenticated users other than a few admins, but the site may allow some users to "register" after which they will be tracked via cookies and a login. When this happens, do they become a Named User? This is not at all clear from the Oracle web site.

-- Randy