Information Management Policies in SharePoint in my experience, are not used that heavily, but are an extremely easy way to apply policies to your documents. They are accessible from 'Library Settings' and are configurable per content type. For example, this means that all 'documents' in the library will have the policy applied.
So what can you do with them ?
This will be visible in the office client application at the top of the document. When the user clicks on the button they are then shown the statement. For example, you could add a message here to say 'confidential document please do not share'. Please note, there is no way to get this policy statement to appear on a non-office client application, such as an image, video, PDF etc.
This instructs SharePoint to do an 'action' after a specified period. The main use would be 'After 7 years of creating this document, send it to the recycle bin, or declare as a record'. This is a great way to govern the documents in your document library. You could also fire a workflow here if you wanted.
This offers the same options as the that available at the site collection level. In fact, if auditing is turned on a the site collection level then this will override these settings. One other point to note is around anonymous access, if you have this configured then anonymous users obviously cannot be identified in the audit log.
If you want to be able to send out a document to groups of users and have them agree or confirm that they have read and understood it, then be able to track who has and hasn't read it, then why not try DocRead ? DocRead is an add-on to SharePoint built by Collaboris. Read more on the DocRead site.