So this is a lead-generating and advertising business model? I agree with the other posters that the value proposition based on your website is still a little vague.
All that said, changing the BROWSER of a user causes a whole bunch of other problems that you will run into.
First, you want to reduce friction of web-service adoption, but require that users change their browsers first? This creates friction where there was none before. A vast majority of internet users still use IE because they think its the internet - not because they made a conscious decision. Its clear you will miss these users (not just because its Mac only).
Other segments could be blocked by IT departments, internal web-app support (I only assume you mask webkit somehow?), or the choice of browsers already installed by other users (kiosk, family computer). Most of the consumer market is covered web-service wise with GMail, Dropbox, and Facebook. Most of this market uses the services their friends use, not something an esoteric browser will suggest to them.
There are other businesses out there that help you 'discover and sign up' for web-based services, including but not limited to getapp.com, appdirect.com, and more integrated solutions with identity management and SSO for organizations.
Now that you have your beta - don't be too inclined to start building complex discovery features that no one will see. Adoption of your browser as the top of the funnel is your primary goal. You first have to overcome reasons to use Safari, Chrome, or Firefox with a unique value proposition they could only get through your browser. Right now a user can use Chrome and go to one of those sites I mentioned and they never had to download and install your product to do it.
I understand the 'lets flip it on its head and get them at the browser level' but thats a war usually fought for different reasons, requires a level of investment probably not worth what you are trying to do with it, and all during an era where desktop browsing is declining in favor of mobile-web and native app experiences are taking over.
Still, I could have completely missed the reason for Raven and what it is trying to accomplish and my response is only based on my experience so YMMV.
IE may be the most popular browser, but it's not used by the vast majority.
Sort of like a dedicated area in the browser that a webapp can add site-wide or page-specific UI controls to, rather than have them anywhere on the page?
Basically, the webapp equivalent of the OS X File Menu or Inspector. That's an interesting concept. Nontrivial chicken and egg problems though in terms of adoption. One approach is a Chrome extension that uses JS to add a "<nav>" element on the left hand side for a select list of sites. The idea is that over time, other sites could adopt this convention and your wrapper might not be necessary.
But are you thinking that you will always want to display these new UI elements in something that is not HTML/CSS/JS? Hmm. Unless you can do some sort of "automatic extraction of UI" from a page...which could actually be super interesting, as the homepage, sign-in button and so on aren't always that easy to find.
That's the sort of thing one could see a browser taking over in a left pane till the site owner got their act together.
Unified with who? If I'm AnnoyingSocialSites.com's competition, why do I want to unify with them?
Beyond that, what are you providing that can't already be done in a standard browser?
It seems like most of the functionality you're providing is already available in Air or Titanium.
Being able to create an app on the fly would be nice though I can see the merits of the app submission process.
The amount of controversy generated here probably means your idea is worth exploring further. Best of luck.