SmartPush was a neat iPhone app from a small startup, Syphir, which allowed the configuration of clever filters for Gmail push notifications. For example, the user could configure rules like "always send me a push notification for all emails from my wife," "don't send notifications between 11 PM and 7 AM" or "don't sent me a notification if the email was sent to more than three people." Our own TJ Luoma was very positive when he reviewed it back in July, and said it was a good way for people with busy inboxes to calm down the incessant beep-beeping of their iPhones.
Sadly, one of the founders of the company has confirmed on a post to their customer service forum that the iPhone app is no more. He's attempting to keep part of the company going, but the other two founders have left, and he can no longer afford the infrastructure costs for the push notification service. He has had to turn it off and remove the app from sale. This means that people who paid for the app during its nine month lifespan (between $1 and $3) are now out of luck -- it will no longer work for them.
The sums of money involved in this case may be small, but the principles are large. The explosive popularity of the App Store, as well as its accessibility to small startups, has drawn many new companies into the fold, and we all know that a lot of apps use the iPhone's wireless networking to hook into always-on web services. Let's be frank: not all of these companies are going to have reliable revenue streams, and when they fold, people who bought their product are going to be left with broken apps and no compensation.
This is particularly problematic for apps that offer push notifications. Because of how Apple structured them, any developer adding notification support to their app has to commit to keeping servers alive to send the notifications through -- even if the app doesn't have any other need for hosting. Once the app sales saturate, the developer is left with dwindling income but a significant fixed ongoing cost hosting and maintaining the servers.