The email app Mailbox is probably the most exciting technology thing of the week, half a million people are waiting in an imaginary line to use it.

Their demo video is really cool, and MG Siegler (in my opinion one of the smartest and least abrasive people who writes about technology things) has been calling it “game changing” for some time.

There’s been a lot of bellyaching and general Twitter rabble-rousing about the wait list to use the app (which I hate to contribute to, although apparently not enough to miss that softball) but I actually have some more fundamental concerns:

• Mailbox is a free download and there’s no way to pay for it, meaning the company has not set itself up to always act in its users’ best interest
• Mailbox has a major dependency on third party platform (Gmail) that it has no influence over

I’m still very excited for Mailbox. Email is one of the biggest problems in my life - Paul Graham said that an attempt to fix email would be “frighteningly ambitious” - and Mailbox is a fresh approach. The design I’ve seen so far is fantastic, and despite my tweets above I actually think they’re handing the rollout in a smart way; nothing gets people more excited than waiting for something.