It is certainly very important to point out how face-to-face discussion is governed by different rules than electronic meetings. However, the matter is far more complicated than we are led to believe in this article. Electronic groups introduces a whole new set of complications and dynamics that have to be considered in this discussion.
The whole aspect of dominance basically takes on another form in the text based electronic medium, but is certainly not absent. To some extent I have to suspect the cited experiments because they contradict my own experience. In face-to-face interactions, those people that have a strong charisma or presence and sport verbal fluidity tend to dominate. The textual counterpart is the control over the written language and the skill to quickly and concisely compose a complelling prose. These two skills do not neccessarily go together. The former face-to-face skills often coincide with higher status, particularly since they get boosted by confidence (stemming from the status). The latter set of skills may be less tied to status, meaning that the other members of the group are as likely to be proficient in text communication. In some groups where this skill does not belong to the highest status person, this would balance against the status privilages (status is of course still visible unless one is using anonymous posting). The point is that I don't think electronic communication makes everyone *equal*, but it may shift the balance of dominance, sometimes to the effect of cancelling out the different factors.
Another issue that arises during electronic group discussion is the level of participation. There is a large difference between a meeting where everyone has committed to show up at a certain time to discuss a topic and a meeting where one contributes when one feels like doing it. In fact, this may partially explain why high status people seem less dominant. It may well be that the higher status members are responsible for more things that demand their attention, leaving them with a feeling of urgency that gives less room for elaboration. In a dedicated meeting however, the focus is clearer. It is also possible that the higher status members don't feel the same pressure to defend their status because they are somewhat detached from what can sometimes feel like side-band discussions. This is especially true if a "real" face-to-face meeting is to follow.
Sending an electronic message is a very explicit act. This is both good and bad. It can be good to encourage people to think before they "speak" in the form of a typed message. The stakes are higher because you may not get a chance to back up your claims or withdraw them until they have been floating out in the open for awhile. However, this can often lead to a situation where half-baked ideas are made to take on a concrete form just so they can survive in the open or because the medium demands a certain level of formality. This may manifest itself in the exchange of more extreme ideas as described in the article. The extremeness in this case having more to do with frozen frames of incomplete thought processes than fully rational conclusions.
The article raises many questions and even though it presents the results of experiments, does not answer them. That is of course because it deals with complicated issues that encompass many different aspects of human social behavior. It is clear that this discussion just taking off.