Last month SkyDrive made some basic changes to the way sharing is accomplished: allowing single files within a folder to be shared, allowing sharing to non-Live ID email addresses, and allowing more flexibility in organizing files and folders on SkyDrive.

While this all “just works”, the guys at SkyDrive have taken the time in two blog posts on Inside Windows Live to dive quite a bit deeper into how the changes were made, and how things actually work “under the covers”.  The first post, from yesterday, Designing app-centric sharing for SkyDrive, part 1 of 2: Complexity of “simple”, and today’s post, Designing app-centric sharing for SkyDrive, part 2 of 2- Rebuilding permissions, take a closer look at how sharing works in SkyDrive, how it originally set up to work back before the days of widespread social network sharing among Facebook and Linked In friends, and what needed to change in order to update the system.

While we won’t go into details on the the challenges the SkyDrive team faced and how they got the new system to work, we encourage you to read the two posts.  Fascinating reading, especially for those of us who are quick to ask “why doesn’t it just do *this*?”.  Sometimes, what seems to be a simple system and a simple request for change is a lot more involved than we think, especially when you’re faced with the scale of millions of SkyDrive accounts, and many times more documents.