Mark Shuttleworth is now telling various publications that eventually they're looking at making Ubuntu updates available on a daily-basis rather than forcing its users to wait for the next major six-month release before receiving major updates to their prominent applications and lower-level operating system stack. Right now, of course, you can install back-ported Debian packages, utilize third-party PPAs, or build new code from source, but it certainly would be nice to see a flow of updated packages arrive for the current Ubuntu release.
This would all be pushed down through Canonical's Ubuntu Software Center (formerly known as the Ubuntu Software Store). Not many other details are known at this time, but again this is a long-term goal and you will not suddenly find Ubuntu 10.10 or Ubuntu 11.04 being a rolling-release distribution. Tell us what you think of this change in the forums.