In 2006 Facebook was all about college. I remember you could even list your classes right on your profile and get grouped with people taking your same classes.
But you're right, "blogging for normal people, restricted to friends and family" sounds like it will always be Facebook's core offering.
Sure but Livejournal could do that. What Facebook is good for is event planning, it very quickly becomes part of your "real life". Google screwed up massively by not integrating G+ and their calendar offering from day 1.
For much the same reason many of Google's other attempts to integrate^Wintrude on people's personal lives have fared poorly. Social integration isn't a coding problem.
But you're right, "blogging for normal people, restricted to friends and family" sounds like it will always be Facebook's core offering.