Main kernel changes in the last 12/15 months?

Hello, I am looking for one synthetic summary of all the main new features and improvements which found their way in the 2.6xx (and maybe 2.4.xx too) kernels since the beginning of 2005. Does something like this exist? I know the detailed changelogs are online, but I don't need *all* those details. If a summary doesn't exist: what would *you* list as main feature/ improvement? Just the feature name is OK, I can find and study it myself afterwards. Thank you in advance for any feedback, Marco