When I think of a PLN it has a different meaning because it involves so many different aspects of communication. Basically anyone you communicate with either personally or professionally is part of your PLN. Collaboration is a huge part of interaction on a professional level it has many advantages because sometimes you may need a little advice from peers and by Tweeting it is automatic info. Here is a link to help explain why Twitter is useful. Your Personal Learning Network is always available so you can learn and teach new things every day. Why not use all the free technology out there to increase your productivity and performance it's FREE! In my PLN I have created a WallWisher which lets you post sticky notes all over a cork-board with things that interest you and other people can respond to what you like. You can use your PLN for professional development as well as locate resources for your classroom. Technology is ever changing and by using the outlets in your PLN you can integrate these resources into your classroom too. A Weebly is another great source for teachers to teach students how to create and communicate with a blog and guess what it is free. NING is another new tidbit of info I learned about that will help expand my PLN.
If you are still unsure about the pros of a PLN and are not sure how to begin Web 2.0 tools will help.