Where do you go when you have a question about something in education or in your content area? Many of us, as educators, are told to continue taking courses and to continue to accumulate hours of time at conferences where people speak at you about things which may or may not help you. What about the people around you (physically and digitally) who can help you? Isn't it a good idea to use the brainpower of other people who you know, can rely on, or trust in general?
That is what Personal Learning Networks are for.
But don't take my word for it...