Image via CrunchBaseMy Gmail Inbox looks like a trash box with more emails from subscribed newsletters or notifications from different web-services than from real persons :)
Notifications are basically worthless after the use. One person has commented on you blog from disqus. XXX has written on your wall from Facebook. You account balance is xxx from Bank Of America. You get the point. The message is not worth after it is read. Ofcourse, Gmail used to say - "Who wants to delete an email with this much storage?" But now they have provided a delete button.
My suggestion is that they should have an easy way to delete all the notifications after 15 days or 30 days after we get them. They can create a addon for that or they can create a template service which can delete the notifications, but it requires the user to add the notification sender email to the list. This way user will have control over what notifications he wants to delete and what he wants to keep. I think it will help a lot in keeping the inbox a lot less cluttered and the volume of email manageable.