Blog by Invitation Only

As more and more laptops roll out across Pennsylvania with the Classrooms for the Future program I am becoming more aware of PA edubloggers.

I definitely see more teachers trying their hand at blogging and especially wikis.

Today I saw something in a blog that I have not seen before. A blog by invitation only!

I understand why someone might choose that option if they were concerned about privacy. Then why blog? The global community is the true power behind blogging. You essentially cut off the worldwide audience who can provide a steady stream of insightful feedback.

Is this technique common? I wonder how many educators use this feature?