At Ubuntu Development Summit held in Copenhagen this year, developers of Canonical have decided to drop alpha releases of Ubuntu, and publish just one beta release prior to final stable release. Thus, next Ubuntu releases beginning with Ubuntu 13.04 will have just one beta ISO.
The decision was taken to ensure better quality of ISO and a more full proof development cycle. Also, Ubuntu derivatives like Kubuntu, Xubuntu etc have the freedom to follow their own release cycles. They can follow Ubuntu's 6 month cycle or choose their own, something new.
The build ISO will be throughly tested to ensure one doesn't face a broken installation in any way. A hardware testing database has also been setup. Much like Fedora, users can submit their hardware profiles to Canonical so that they can choose on what hardware to focus more and improve hardware support.
The details were published in The Orange Notebook blog.
The Release schedule has dropped all alphas, and the first beta, resulting in a beta and then final release milestone only. In addition, the freezes have been moved back a few weeks. The end result is the archive will not be frozen till late in the cycle, allowing development and testing to continue unencumbered. This of course is for ubuntu only. Which brings us to flavors!
You can read the blog post here.