While I don't usually blog about my day job as the Dev Manager for Windows Live RSS/Alerts, this has to be mentioned.
Last Thursday, the Windows Live Spaces team propped a release to production that enable seamless integration with Windows Live Alerts. The rollout is limited to English language Spaces first, with more to follow. From the post:
Be instantly notified of changes to your favorite Spaces!
It’s now even easier to find out who updated what on their Space and when…and you can be one of the first to find out! You can now sign-up to receive updates in real time for blogs, photos, lists and comments in your favorite Spaces. Simply click on the “Sign up for alerts” link in the Visitor tools module of your favorite Spaces and start receiving your updates right away. We want you to try it out and tell us what you think of alert, so we’ve limited this new functionality to English Spaces first.
We wrote quite a bit of the code when we were MessageCast - it is great for it to finally see the light of day!
As you might imagine there are a number of technical challenges working with a service as large as Spaces. Kudos to a lot of people for making it happen.
If you are interested in integrating with Windows Live Alerts, check out the SDK.