I would love for this to keep expanding to more inboxes, and beyond to news feeds and other kinda inbox-shaped things. Why not aggregate Facebook news feed, Instagram, Twitter, Reddit, HN, your local newspaper, etc. It's what Google Reader woulda/coulda/shoulda become.

Please, break down the walled gardens. Free us from the whims of the product managers pumping out redesign after redesign for all the services we use.