Thinking more about the idea of weblications, I was wondering why we haven't seen someone like Hotmail or Google release a true web services based API on top of their email services. There are lots of efforts to drive access to Google (see here
for one) via HTTP requests, but these are really shims and not true APIs offered by Google a la similar services you see from Amazon and eBay. I couldn't find any similar efforts for Hotmail, but I didn't dig to hard.
Of course, Google now offers POP access, so maybe that eliminates the need for web service APIs. Hotmail is also available via clients like Outlook Express and like clients. But it still seems more natural in this day and age to expose stuff via web services, especially if you plan on adding other services like calendaring, file storeage, whatever. It would be cool to point to a WSDL on Google and suck in email services, calendaring, file storage, etc. Maybe its out there and I just haven't found it after spending 1.48 minutes researching this.