I thought I would test this hypothesis by looking through the online forums on Linked in.
The graph below shows the results of a quick survey of 30 threads within one forum. Columns are marked with a Q if the thread was started with a Question, S if it was started with a Statement such as a link to a blog post. The blue length of the column represents the posts within the thread that were statements; the red length represents questions.
We can see several interesting things.
Firstly most of the threads that start with a statement, have no replies at all. No discussion.
Secondly, there are very few questions among the replies, either to the questions or to the statements. In totla, fewer than 10% of the replying posts are questions. I think that supports the idea that what we are looking at here is not dialogue as such, where questions and answers are more evenly balanced, but a set of stated views.
There is one discussion I would like to highlight however - it has the largest number of replies and the most comprehensive discussion, and you can find it here
Part of the reason that this thread is so long, is the involvement of the person who originated the thread (take a bow Gerald), and his activities in responding and reframing the discussion, and the social interactions he generated. He has taken the role of discussion facilitator, and as a result has a far longer and richer result.
Out of the 98 posts within this thread, 63 are declarative statements, 13 are responses and reframing, 14 are social (expressions of thanks and appreciation), and 8 are questions.
For me this thread, although still more Q&A than dialogue, expresses much of the richness you would like to cultivate within a community of practice.