Over at LWN.NET there is an interesting post via E-Mail about the new /run directory being introduced in Linux.  Why should you care about /run.  Well that is what the bulk of the E-Mail/Post is trying to explain.  The short answer is that /dev has been being misused for some time now.  Run time data should go under /var/run.  BUT /var may not be available early enough in the boot process for some purposes.  Things like Software Raid will be needed earlier in the boot process than /var may be mounted.  So the programmers have abused the fact that /dev is there almost as soon as the system starts booting.  This change will make the new directory /run appear at the same time that /dev is and be for use by these types of functions.  

Almost every distro has agreed to implement this and you should see it start rolling out to your favorite distro over the rest of the year.  Back ports will probably not be made since applications will take longer to update for the change.