IRL social circles are also, for the most part, geographically constrained to those one meets in everyday life. Possibly geographically distributed for professionals amongst co-workers or contacts within ones career track.

Online echo chambers, for better or worse, collect those of a similar interest and/or ideology from around the world. As with, say, Hacker News.

That may be benign, or it may not be. The inspiration and action are what matter. But the end result is that groups that would have no capacity to form and organise through physical contact, and which would be only very weakly integrated through print or broadcast medium, can emerge online. Again, that might be a positive or a negative development.

But what it isn't is either equivalent to IRL associations or a continuation of previous patterns of organisation.

And to that extent, Petersen's claims are grossly disingenuous.