tl;dr;

• -stable kernel releases stay the same
• this proposal is how we pick the -longterm releases
• -longterm kernels will be picked every year, and maintained for 2 years before being dropped.
• the same Documentation/stablekernelrules.txt will apply for -longterm kernels, as before.

History:

2.6.16 became a “longterm” kernel because my day job (at SUSE) picked the 2.6.16 kernel for its “enterprise” release and it made things a lot easier for me to keep working at applying bugfixes and other stable patches to it to make my job simpler (applying a known-good bunch of patches in one stable update was easier than a set of smaller patches that were only tested by a smaller group of people.)