The stream view is an interesting concept, but we've found that many people don't have a nice inbox of messages as shown in the preview. In fact, it's quite the opposite: messages from friends, family, and coworkers are often overwhelmed by notifications, newsletters, and mailing lists. However, your Amazon shipping and Twitter notifications aren't spam, you just don't want to see them in the same context.
I'm working on Glider (http://glider.io), a fix for the mess in your inbox. You already know which kinds of emails are important to you, so instead of obscuring that information, we think the best solution is to sort and display emails by sender and context.
We did a soft launch on HN a few weeks ago (http://news.ycombinator.com/item?id=3519917), and would love to know what you guys think. Good luck as well to the Fluent team!