Canonical is currently following an interim release strategy, with a new operating system popping out every six months, but this strategy is about to change.
Canonical is probably the only company capable, at this moment, to develop and deliver an operating system right on schedule. They are never late and just like clockwork, every six months a new OS is launched.
The launch dates are in April and October (the 04 and 10 numbering is pretty clear) and every two years they release an LTS version (long-term support).
The strategy might seem sound, but the fact of the matter is that it's no longer viable for the current market. Every time an LTS comes out, the following releases are not picked up with the same frequency, even if they might be better.
A comprehensive interview with Leann Ogasawara, Canonical Kernel team manager, has been uploaded on YouTube by Ubuntu OnAir, has she had some interesting things to reveal.
It seems that Canonical seriously contemplates the possibility of switching to a rolling release schedule, which means that only the LTS versions will be actively developed and Ubuntu 14.04 (Tempestuous Tinamou?) could be the first in line.
This is actually good news. This decision would free the developers to work on bugs and other problems, instead of worrying about multiple kernels, for example.