Alan Kleymeyer has a post entitled NewsGator Online where he writes

I've switched my online news aggregator from Bloglines to Newsgator.  First, I wanted to try it out and compare it to Bloglines.  I like the interface better, especially in how you mark things as read.  I've swithched for good.  I mainly switched so that I can continue using RSS Bandit and get the benefit of syncing between it and an online news aggregator (supported in latest RSS Bandit 1.3.0.38 release)

Alan's post describes exactly why creating APIs for your online service and treating it as a Web platform and not just a web site is important. What would you rather use, a web-based aggregator which provides limited integration with a few desktop aggregators (i.e.Bloglines) OR a web-based aggregator which provides full integration with a variety of free and payware aggregators including RSS Bandit, NetNewsWire and FeedDemon? Building out a Web platform is about giving users choice which is what the NewsGator guys have done by providing the NewsGator API.

The canonical example of the power of Web APIs and Web platforms is RSS. Providing an RSS feed liberates your readers from the limitations of using one application (the Web browser) and one user interface (your HTML website) to view your content. They can consume it on their own terms using the applications that best fit their needs. Blogging wouldn't be as popular as it is today if not for this most fundamental of web services.

The topic of my ThinkWeek paper was turning Web sites into Web platforms and I was hoping to get to give a presentation about it at next year's O'Reilly Emerging Technology Conference but it got rejected. I guess I'll just have to keep shopping it around. Perhaps I can get it into Gnomedex or Mix '06. :)