Apple unveiled the iPhone 5 on September 12 and the following day updated the iCloud.com web interface by dropping the Beta flag and introducing the new Notes and Reminders web apps with cloud notifications enabled. Today, club Cupertino improves upon its cloud-based suite of services by adding shared reminders to the Reminders web app on iCloud.com.
You were able to set up shared reminders using Reminders on OS X (not via the stock iOS Reminders app, though), but those wouldn't sync with the web interface. Today's update is a minor but important one as it finally provides for a more seamless sync of reminders across devices, though not yet perfect...