The upvotes could also mean that people appreciate a good presentation of introductory material, and they may see a use for it as something to send to the newbies on their team.
I'm one of those. I keep a list of good intro material I can send to friends, nephews, etc, who want to learn programming. HN and reddit are two good sources of those kinds of posts.
For this subject, I usually send people to Bill Kent's Guide to the Five Normal Forms: http://www.bkent.net/Doc/simple5.htm