First of all, this looks very nice and I have nothing bad to say about this particular product at all.<p>But I can't help but wonder why there are so many apps like this. Off the top of my head there's Notable, LayerVault, Shipment, Cage, Marqueed, Moqups, the recently released Flatsie, and a ton of others that all offer some variation of the "show your work to clients" theme.<p>I'm really curious what pushed you to release your own version of this. Does Draft do something that, say, Notable doesn't? Or do you think the market for this is so big that it can comfortably support one more similar app?