At the beginning of the school year, I did several sessions in-district on using Twitter as a 24/7, self-directed professional development tool. What I failed to do was publish the link to a great resource that lists Twitter users by the subject area they teach. Thanks to a blog post from Alice Keeler, there’s now a pretty comprehensive list of educators you can follow. Try some out and see what gems you find. Be sure to add yourself to the list, too.