When Mailbox for iPhone launched last week, it did so with a somewhat unusual "reservation" system. The team behind Mailbox was only letting in a limited number of users at a time, so unless you registered early you were stuck with a countdown of how many people were ahead of you in line to get access to the app. That didn't stop Mailbox from suffering a pretty major outage yesterday, but the makers of new "smart calendar" app Tempo are implementing a similar system. The Tempo team submitted a new version of the app to Apple today, and it'll include a reservation system. Users can sign up for a position in the reservation line, and Tempo will email the users once the app is usable.

Until that new app rolls out (Tempo says it'll likely be out within the next 24 hours), the developers are "gate-keeping" new users — between 1,000 and 3,000 get access ever hour, and there's currently a waiting list of "well over 100,000 users." While we understand that new apps like Mailbox and Tempo can often go through growing pains, it's not the best experience for those looking forward to using them. Of course, it's probably better than the app failing to work entirely thanks to a flood of users, but but we'd rather just see these apps be built to handle the flood of eager iPhone users from the start.