First, I'm absolutely convinced that Enterprise 2.0 (it's concepts as you have defined them) will alter they way organisations communicate and collaborate. I would place myself in the camp that believes that the technology enables process change and therefore corporate culture. But in my opinion, it will not alter the enterprise as a structured ensemble of people working towards the same goals (at least in an ideal situation), with necessary layers of management and structured processes.
I do agree however that companies have a intense need to capture the informal information, processes and knowledge. In my experience it is often so that informal channels are quicker to disperse important information than the formal ones.
In fact the smaller the organisation the more likely that informal processes rule the organisation.

Isn't is also true that Enterprise 2.0 too is an attempt to structure unstructured information? or at least capture it and make it more usable and traceable ?

I see the new technologies and ideas that Enterprise 2.0 brings as an extension of existing technology and structures, not as a replacement. They will open up a source of information that hasn't been tapped efficiently in the past.

My definition of an online community is available here http://bit.ly/63sBDQ

Also, at that time, most information sharing and collaboration strategies focused on activity-centric improvements – collaborative tools were often applied to more structured (semi-formal or formal) activities and were often designed to improve certain outcomes. In general, solutions were localized, lacked visibility and lacked transparency.

As platforms, infrastructure, and networks matured to where they are today, we have legacy ESSPs. I think that's an important point so we can think of this as part of an evolutionary technology trend. These older ESSPs were fine in their days (focused on activity-centric participation models) but not solving some of the intractable issues that organizations face now. The current incarnation of ESSPs take on a different focus (more “Web 2.0″ styled).

I agree with you on the formal/informal organization point but would phrase it as 'formal vs. informal participation structures” or models, just to get away from the scare tactic that you have to turn the organization upside down etc.

To me, a key concept of E2.0 is that more visible/informal participation structures and more transparent/collective contribution patterns will create network effects that in turn, generate business value.

The ESSP role in that model though s that of an enabler – it is a quesiton of 'how used” vs. 'what is” – else we fall back into a very techno-centric view of things (repeating many of the mistakes of KM in the nineties).

ESSPs defacto can position you to participate and contribute – but you need the behavioral/cultural practices to happen within an organizaiton (e.g., design, user experience, adoption, change management, etc) to leverage the benefits.

Or, are you talking about the emergent use of social software vs the software itself (which is somewhat techno-centric)? If the focus is on “how social software is used” then we're back to a more non-technical discussion around design, user experience, participatory models, culture, etc.

Open questions:

1. What is social software?
2. What makes a social software platform “emergent”?
3. At what point is an ESSP no longer emergent and when that happens, what has changed?
4. What other historical examples of emergent social software platforms are there and what can we learn from them? Ex: e-mail, Lotus Notes