The Palm Foleo, announced today, and Google Gears, being announced tomorrow, both have impacts on the calendar landscape. The Foleo offers a "large screen" cell phone experience, but the initial product doesn't bring cell phones' calendars to the large screen unless they're Web-based. Google Gears will, in time, make Google Calendar truly an "always-on" app by allowing easy offline access.
Palm missed an opportunity to lure back some customers lost to other calendars, or even paper, since using a calendar on a typical cell phone is cumbersome at best, and adoption of Web-based calendars over cell phones is just beginning.
Google still has yet to address growing privacy concerns. For instance, when will Google Calendar users be able to store encrypted calendars? Simply storing them with a secure HTTP connection (https) would be an improvement, wouldn't it?
Google missed an opportunity to address this, but since taking Web applications offline represents such a large step from the state of the art, the world will forgive Google for now.
None of which has much to do with improving calendar interoperability. Generally, I avoid commenting on calendar tech in itself here. But I've been thinking of tweaking the mission of Calendar Swamp from plain "interoperability" to "security and interoperability." Let me know if you support the idea, or if you consider it mission creep.