Twitter for teachers

When I first heard about twitter, I thought it was a waste of time. Why would I need to know what others are doing, thinking, reading, right now? I was attending EVO 08, and everybody was so enthusiastic about social media and web 2.0 tools, that I couldn't resist following the flock.
Now Twitter is creating my own PNL (personal network learning), which is essential for CPD (continuous Professional Development) in the 21st century.
I´ve just found a song about twitter...
"You´re no one if you´re not on twitter" Hilarious!