If you read KernelTrap lately, then you will notice that the posting is more frequent, meaning more hot news inside the linux kernel mailing list and Jeremy has summarized it for us in order to stay up to date with the latest kernel development. After kernel 2.6.22 has been released, Linus opened a merge window, which is a phase where most of the big changes are accepted and then when RC1 is released (meaning merge window is already stopped), they tried to fix things rather than adding new features on the kernel itself.
In this merge window this time, big changes has been integrated in the kernel mainline. You can see the whole details on Andrew Morton's plan for 2.6.23 but here's the main topic (and more human friendly), for example, Ingo Molnar's CFS scheduler, Tickless Kernel for x86-64, Rewriting x86 setup code and boils them as one code (Andika has a post about this), 2 new documentation translations for Japanese and Chinese, lguest and Xen Virtual Machine gets merged. Isn't that great? Lots of new features on the main kernel, but as the trade offs, the kernel size will be bigger than the previous 2.6.22.
I don't know why the translations are being merged (i haven't read the post yet, but i will soon after i post this), since more and more translations will come up and the kernel will be bloated with translations for many languages. I'm not saying documentation is a bad thing. In fact, documentation is very essential, but i think it deserves in other places rather than in the mainline kernel. Not every one will read the translations, as it requires you to understand Japanese or Chinese language.
I only wishes that it will be a smooth release, just like 2.6.20.