great article, I enjoyed it.
You mentioned people can be afraid because they don’t see themselves as experts.
Another point that I think holds lots of people back is fear or failure.
Using your blog example you are totally right about the costs of failure being no one reading it, but for a lot of people that could be quite a confrontational thought.
i.e. not doing anything and not succeeding is easier then doing something and failing

“I usually tell these people to start a blog. Usually they scoff at the idea and instead just keep their writing private.”

I’ve come across this in my life, too, and people who don’t put forth a little of themselves to reap the benefits of expressing to the bigger world are self-limiting in other ways too. I quip sometimes that subconscious spontaneity — like the brilliant joke that materializes “on the spot” — can be the best stuff for a blog post (instead of trying to “think hard like an ‘expert’ and write something ‘substantial’ later), but all too often, the people I’ve suggested this to (all of which have a GREAT sense of humor) haven’t gone forth with it. And I lament.

thank you for investing so much time in inspiring us to live more fully!

you rock!