This is a developer’s worst nightmare. Spending your time to get an application to talk with another one just for the sake of it is hard to swallow. I understand it’s part of the development cycle. However, while you are working on the integration, who is iterating new updates to users?
And so when Flickr hit the ground at Yahoo it was crushed with engineering and service requirements it had to meet as per demands of the acquisition integration team. Those were a drain on resources, human and financial. Even though many of the resources came from Yahoo, they were debited against Flickr. This created an untenable cycle that actively hampered innovation.