I can't say I disagree with Liz on this one, but I think she's hit on at least one larger problem with LinkedIn: self-selection. Most online communities are self-selecting because of the limited role of chance and accident in encouraging participation. You can't "just happen to" join – members have to take an active role in order to participate, unlike many real-world communities. But Linked In is a community that's more self-selecting than most. Like Friendster, it operates on an invitation mechanic. In other words, when you join the network, it's as a friend of someone who is already in the network. But unlike Friendster, there's significant social cost and effort required to make contact within the network. One thing that keeps Friendster vital as a community is the "random Friendster friend" effect – the costs of adding a new contact are low and have few consequences. In LinkedIn, you are explicitly taking on a professional role, and for that reason people are more likely to think twice about who they invite, who they make requests of, and who their connections are. Are women more likely to be affected by this? I'm not sure, though I would guess that it's likely to exaggerate existing gender disparities in the field. If we're going to figure this out, here are some statistics I'd like to see: * Number of women vs. men invited in various fields * Number of women vs. men who accept their invitation * Average number of contacts for women vs. men * Average number of requests made/sent by gender * Average membership length for women vs. men * What kinds of people women vs. men plan to invite Of course, self-selection isn't always a bad thing. Communities can't function if they don't have some organizing ethic. (If everyone is a member of a given community, then no one is!) But I think the way LinkedIn handles this issue is going to cause it problems with gaining and retaining a diverse set of members in the long run.