Very nice UI/UX. If I was a .NET developer this is something I would consider using and paying for. 2 initial thoughts:

1. It's not clear how the integration works (API call during exception handling?). That mechanism is important to me, the developer. 2. Seems like the ASP.NET limitation will make it tough to gain traction initially.

You may want to consider open-sourcing the integration hooks (API calls, stack trace parsing, etc). That would allow people like me to add support for my language/framework and send a pull request through GitHub. Just a thought..

Best of luck!