It was about 30 minutes later when I discovered that. :facepalm:
A problem for me is that the intro sections, which really are very valuable, are positioned far enough below the main icons of a section's home page that they fall out of sight. On my display (a Windows7 notebook), I have to remember to go look for them. Unless I go to the section home page and scroll down, I miss them. This is my mistake, of course, especially considering that the content usually holds such valuable material.