Deism: the belief that the Universe was created by some supernatural power, but that this entity does not play an active role in the Universe today.
Deism asserts that there needs to be some supreme authority to 'get things moving' but minimizes the role of that authority to be involved in the subsequent day to day goings on, i.e. enjoying that seventh day of rest forever.
For web identity, this is the UProve proposition. To a lesser extent, Liberty's Advanced Client.
Theism: the belief that the Universe was created by some supernatural power, and this supreme authority even now playing an active role in day to day happenings.
Like deism, theism postulates a creator, but has that same creator actively participating in the Universe's happenings once initiated, i.e. answering prayers, causing floods, chatting with Presidents etc.
This is the SAML Web SSO, Managed Cards, & OpenID proposition.
Atheism: the rejection of theism and deism.
Atheism rejects completely the necessity or relevance for some deity mediating between individuals and the wonders of the Universe.
Think Personal Cards.