But I disagree somewhat with your comment about a clearly defined message. They do have a message and, while not clearly defined, it is clearly Marxist. They are after an end to Capitalism and the installation of a Marxist government. That is why you see no real objection to Obama. They know that he represents their best chance of achieving their goal. Scary stuff to say the least.
Take a look at their Manefesto: The99PercentDeclaration.
Read it. There is a bit of libertarianism in it but those elements are swamped by the Marxist content.
Note also that it infers a level of organization or at least organizational goals that have not been widely discussed in the MSM or even here on FR.
You're right. They definitely do have a Marxist theme or common thread to their disjoint messages.