Technorati searching over 50 million blogs.......
Now that is truly mind-boggling.....or should that be mind-blogging?

The scope and potential of these things is amazing.

Del.icio.us is fantastic

As an ex teacher I would think tagging would make organizing and developing curriculum and lesson plans ever so much easier, and lead to much greater sharing of ideas and resources at individual student, class, school, region, even state level.
As a life long learner, traveller and grappler with new technologies, the concept of tagging has many interesting and manageable possibilities for me.
As a Library worker, I see tagging useful for relevant on line group training, socialising and sharing interests at staff level. Also as avaluable shared tool for homework and reference quieries.