The first is Lunarr. A document-centric collaboration tool. ReadWriteWeb has a post on this tool and explains what it does. They do have some problems with the concept too.
What I like about the concept is that it that Lunarr seems to do is to keep communication about the document (could also be a wiki-page) close together. And that's wonderful. The conversations about the document gives context to the document and gives information about the history of the document and the choices that were made. And this is done in one place. When using wiki's the versions are saved but the communication about the page is saved in the email client. You have to flip back and forth between the wiki and the emails to retrieve the context of the wiki-page.
Another "email-context-giver" is xobni. Xobni tries to do smart stuff with your email right in Outlook. It gives all kinds of views on your email, contacts, etc. It reminded me of SNARF.
Xobni creates context in a different way, by analysing your emails, extracting your social network, the previous conversation you had with a person of group of people and the attachments you share with them. It presents all this information in a sidebar in Outlook.