During JavaPolis we had a very good presentation by Bruce Eckel called 'Unconference'.

"An unconference is a conference where the content of the sessions is created and managed by the participants, generally day-by-day during the course of the event, rather than by one or more organizers in advance of the event" (WikiPedia).

The agenda of discussions is negotiated between the participants and those discussions than happen in open spaces.

I like it because I have more and more difficulties to follow a long session without interacting. Also often when you go to an event, the good part is not the presentations but rather the contacts that you could make. Very often what I retain from a presentation is the name of the speaker so I can ask him questions later.

In an unconference, you must think "conversation" and you must be interested in this conversation otherwise you drag the energy of the meeting down.

My feeling about unconferences is that you should carefully choose the conversation topics otherwise you'll might have some problems. I especially think about the problem of having conflicts of interests among participants (competitors for instance). So I guess it would be more interesting for a loose network rather that for one-to-many communications.

But I'm looking forward to participate to or organize an unconference !

See an example of unconference here : http://mindview.net/Conferences/ProgrammingTheNewWeb