Thank you Barry Wellman for introducing this very informative and interesting thread. There is a general context in which lurking is not desirable. Before the digital age there were public libraries. Even thought the books in the library were available and use was free and encouraged, most people were "lurkers" or perhaps more correctly non-users. On most long established lists, many of the registered members are no longer readers. Another group that my experience tells me is almost as large, read occasionally selected topics but seldom if ever respond. Several of you are clear about the benefits of people who are unsure what they have to say, just keeping quiet. "Less noise" is desirable. But Peter Timusk is also correct in his observation that expounding half baked ideas and exposing one's lack of understanding is part of the active learning process we are all engaged in. People who lurk, excessively may assume that they are saving time. It is my contention that they are missing learning opportunities. Once you commit yourself to an opinion in public you begin to pay attention to the reaction to that in a way lurkers seldom understand. Paying attention increases your learning rate because you are now involved. (The hen and the pig are involved in producing my breakfast in quite different ways too.) It's that sort of difference. So for me there are two ways in which lurking is undesirable. The first sort of lurker, is "lurking not present". Absent from the discussion. A non-user of the library. The second sort lurker, is "lurking but not engaged". Present, borrowing books, reading, but never discussing what was read and never attempting to use what was read in any practical way. Involved like the hen is involved in my breakfast. Participants in the discussion on the other hand, are involved like the pig. The is something at stake. Jericho Burg identifies that sort of lurking that is highly desirable. She says' "For me, subscribing to lists is one way of finding out what conversations are going on in a particular field" ... in which she is not familiar. So true Jericho, which is precisely the reason who I'm part of this list, while my fields are more, Education, Innovation and KM. John S Veitch http://www.ate.co.nz/