/This is just a small update
The "New applications" mystery has been cleared by Rick Spencer in a comment to our New Post-Release Repository For New Applications Starting With Ubuntu 10.10 Maverick Meerkat post:
As the blueprint author, I can clear up the ambiguity. I apologize for the lack of clarity. It will be cleared up as we document the process.To be clear, this blueprint covers delivering *new* apps into a current release only. By "new", these are apps that are not in a Main or Universe when a version ships. It does not make Ubuntu a rolling release. You will not be able to get the latest versions of apps like Firefox, Open Office, etc... from this method. You will still need to get latest versions of those apps from their respective PPAs or upstream sources.
Update: However, like Starks (thank you!) points out in a comment, this won't be the case for Firefox, as Ubuntu Hardy, Jaunty, Karmic and Lucid will be getting Firefox 3.6 soon. Further more, Hardy, Karmic and Lucid will also get the new Firefox 4.0 (Jaunty is still uncertain).