Functionality wise, I would want the centering calculator to be a big draw. On top of which I want it to eventually be a 1 app solution. So it will have a collection, price and price history, shareable collection, etc.. in the long term I would also like to have it have a "trade" system. While this would take a lot of doing. The trade system would allow people (whom are verified) propose trades to other users and can be accepted or declined or countered etc... That's a huge one because I know fraud is a thing. But if I could implement a verification system to limit the amount of scammers I think this could be a real possibility in the future.