Tap Tap Tap recently announced that it has sold 2 million copies of its popular “Camera+” iPhone photography application. In a blog post, Tap Tap Tap principal John Casasanta noted a couple of compelling figures about sales of the app. First: Just 5% of Camera+ customers purchased the $0.99 “I ♥ Analog” filter each day.  In contrast, more than half of Camera+ users apply new updates within 6 days of a release. Casasanta admitted the low sales could be because Camera+ doesn’t aggressively push the in-app upgrades, but he noted that those in-app purchases pull in about $70k over a 4.5 month period — a figure that’s relatively small compared to Camera+ sales. “There are companies with free photography apps that are trying to have their business models revolve around selling effects via in-app purchases, but it’s very unlikely that this can be an effective business model,” Casasanta said. We’d be interested to know if gaming developers feel the same way.

[Via Apple Insider]