Learning Communities

Ive been thinking alot about learning communties, or personal learning networks. Ive been thinking about what they are, do they even have definitions or parameters. I mean I add you as a friend in facebook or reply once to your blog, are we really part of the same learning community? Can I belong to a learning community as a passive participant, peaking into your blog and  secretly reflecting on what you or others have written. Am I now part of your learning community? Then when I reflect on my class, kids are doing the same, some talk more than others, some share more than others. I guess being in a box together makes us a learning community? or does it?  Im still coming to grips with this. I think the future of learning is through collaboration, its happening now but community somehow suggests some knid of bonding, sharing or interaction.