I was working on a the last note and wanted to check things out under a fresh install. I decided to make a new Mac User to accomplish this. I used GitHub for the Mac, Safari on the Assembla site and the Tumblr site, and the command line. When I finsihed my work, I idlely was thinking about keeping this user account around for the next effort or deleting it. One of the consideration was how much space was in use by the account. I was shocked to see that the home directory took 330MB!
Looking into it, I found the bit space was 300MB in Preferences. The other two large directories was Caches (30MB) and Applications Support (12MB). Inside preferences was a folder SMDHelpData that was the space user. This folder evidently has the help file information: info, caches, and indexes for finding things for all the applications on the system (not just those that had been used). I am guessing there is a distinct copy per user since in theory at least, one could through security settings block different users from various components. There may also be some personalization (highlighting, last location, etc.) capability.
I was very surprised at how much space was taken but I decided my lesson was to also trade space for functionality (enough performance) and leave the user configured so I would not spend time repeating the building of this space.