This news is a few days old but I thought it worth mentioning. Canonical has announced that the non-LTS (Long Term Support) release cycle is being reduced from eighteen to nine months. The primary reason seems to be the resource load for supporting non-LTS releases.
The changes start from 13.04 (scheduled for April 25 2013): LTS releases will be supported for five years.
Sources & References:
- Ubuntu Fridge: Changes in Ubuntu releases decided by the Ubuntu Technical Board
- Ubuntu Wiki: Rearing Ringtail Release Schedule