PLC vs PLN?

This past weekend, I participated in a Twitter chat called #satchat. In my opinion, it is one of the best run edchats out there right now. Though it takes place at 7:30 in the morning, I try my hardest to participate each week, as I am always learning something new from the amazing people who also participate. It's a HUGE component of my PLN. The topic was centered around the concept of ensuring students are learning in an environment that will help them to succeed in a world that is growing smaller by the day thanks to advances in technology. During the chat, educational best practices were discussed, including the use of the PLC (Professional Learning Community) framework to drive instruction. One of the chat participants brought up a very interesting question - is there a difference between an PLC and a PLN (Personal Learning Network)?

I've spent the past couple of days seeing what other people say about this. 

Lorraine Boulos shares the following in her blog, Making Shift Happen. It seems to me the "PLC" has become synonymous with Professional Development and often, it is the principal, consultant, coach, or whomever the "Instructional Leader" is in the building, that decides what everyone needs to learn about.  How and why does this happen?  These instructional leaders are not just being arbitrary. They are looking at student results, looking at the gaps, and then they are using professional resources to determine what is the best strategy to meet the needs to close those gaps.

Furthermore, Russell Munkler put together a great slide presentation to help explain the difference between the two: http://www.slideshare.net/rmunkler/developing-your-pln

From what I can best gather, a PLC is goal and data driven - within the field of education, that goal is usually student academic success. A PLC is basically designed to function for the good of the group. A PLN, however, is designed by the individual, and its purpose doesn't necessarily have to be aligned to that of your school or organization. A PLN is broad, and it doesn't share the constraints of time or location usually placed upon a PLC. In addition, the "P" in the PLN appears to be interchangeable. While in most cases, the "P" stands for "personal", I've also seen it stand for "professional". 

If you read back to my other posts, you'll find I am a BIG fan of the PLC framework. I've witnessed AMAZING things happen as the result of educators buying into and working as a PLC. That being said, I am beginning to wonder if we shouldn't shift our thinking. Is the PLC too constraining? Can you still have a common goal working through a PLN? If we are asking our teachers to prepare students to be successful in a global society, I think it is something worth looking into! 

Thoughts???