At my library, we use email primarily for communication--receiving information from and sending information to colleagues, other organizations, vendors, presentors, etc. At this point we do very little communicating with library patrons by email. I would say that more than improving productivity, email has changed it. Because it's easier to be more informed, and to exchange information, being more informed and exchanging more information has become part of what we "produce" so to speak. It is certainly easier to send out information or ask questions of a group; deleting spam (and I'm thankful for the filters so there isn't MORE of it) takes up a bit of time each day.
I think that with time, the ways in which we provide reference information will change. At present, our library has a staff of 2; both of us work fewer than 40 hours/week. I think between meetings and staggered schedules, the hours during which we would realistically be able to provide instant messaging reference would be erratic enough that they would be more frustrating than useful to patrons at this point. I would guess that other small libraries are in similar situations; perhaps teaming up to enlarge the pool of people available to provide IM reference coverage might be one way for smaller libraries to move into that area.
I attended about half of the "Casual Conversation with Michelle Boule" in the OPAL auditorium. It was interesting; between the audio, chatting amongst the participants and responses to the text messages by the presentors, and the web cobrowsing, it was more interactive than I would have anticipated. I can definitely see the usefulness of web conferencing to allow more people to participate in conferences than might have the funds or time to travel and attend. I would note, however, that in my experience, the value of the conference is not only in the formal presentation/learning, but also in the informal chatting that happens between row or table-mates, or over lunch. I would wonder to what extent, without the face-to-face connection or physical proximity, people would stick around and visit and exchange experiences and information. Another possible shortcoming might be the loss to the presentor of facial cues giving an idea of the extent to which their audience is following or comprehending the information. On the other hand, having the conferences archived, and having the ability to listen to them again, to go through the information more slowly and trying things out or reading more of what was on the screen, could be a plus of the format.