I've been thinking similarly around this topic and would like to share three perspectives/roles I've been sharing with educators in my area:

1) Personal/Professional Learner
I agree with Marianne that our PLNs have been with us for as long as we've been learning. We have F2F interactions (I hope) more often than online and we cannot discount those around us (as well as books, periodicals and traditional media) as nodes of our networks.

2) Classroom Practitioner
More often the default for educators looking for resources. At the same time, this often hinders the personal/professional learner because they dismiss the personal use as wasted time or not immediately relevant to what they do as educators.

3) District/School Leader
I like to compare this to the star athlete who becomes a role model even though they didn't "sign up" for it. Quality teaching/learning always draws attention and should be shared in some form. What I think is important here is that assuming this role on some level solidifies the F2F nodes of our networks and benefits both perspectives above.

In summary, I think looking at the our roles within a PLN is important in the development and it keeps us away from getting caught up in the tools which is too often the case.

What do you think?