Sounds useful, but I'm not sure I'd pay for this service. The ExceptionNotifier plugin does a good enough job, and exceptions shouldn't really keep happening for days on end. In my app(s), when there's an unexpected Exception, it gets fixed within a few days at most, so I'm not quite sure how useful a historic view would be.
Very nice looking. This could be a easier way to find which bugs bubble up to the top most frequently. Swombat does make a good point though. We use ExceptionNotifier and the policy is to fix anything that triggers it, so we normally have zero exceptions occurring.
If you could maybe have it tap into your logger so you could log weird states or other issues that don't cause exceptions, but you don't want occurring often perhaps it would help a little more (recoverable problems).
