Nice analysis by Joyce Park on Web Services Commons:

Flickr is a company that has gotten into open web services in exactly the right way. It costs them a lot of money to host all that bandwidth, but feeds of photos are a cool new feature and a value-add to their users — and ultimately it all loops back to their core business model of getting people to host photos on Flickr. Flickr’s API also gives users some confidence that the company isn’t going to try to screw them by making it hard to get their content back out if they want to take it and go elsewhere. It’s a win-win-win situation for everyone, and another example of Flickr’s leadership by clarity.

On the other side of the spectrum are companies that treat RSS feeds and public web services just as free content, without adding any new transformative value or giving anything back to the community. There’s nothing necessarily wrong with this if the license allows it, but it’s not interestingly different from screenscrapers who present your content as theirs — who have long been considered sleazy parasites by most of the legitimate web. The whole idea of opening content via web services is that growth for all can be enhanced by sharing — and in the long run people don’t want to share with those who are openly contemptuous of the whole idea.

Opening content via web services used to be the Holy Grail, but slowly the world is rewarding the owners of services that do just that, as the Flickr example illustrates.