Networks expand by invitation. I received several independent invitations to LinkedIn before I decided it was worth joining (since that gave me a ready-made network on LinkedIn). I have started to receive invitations for other networks, but I haven't accepted them yet. This is an example of the Change Agent Cascade pattern.
While these networks may be useful, there are several problems with them.
1. Commitment. If I join a network, I need to make it work for me.
This means loading some contacts, carving a profile, responding to
contacts. This is a cost, which I incur in the hope of some
professional, social or other benefit. If I am not willing to make any
effort, I might as well not bother.
2. Ambiguity as to the purpose of the network. Some networks have a
rhetoric of mutual support, endorsement and referral. But it is hard to
see how this purpose can be fulfilled when people load hundreds of
undifferentiated contacts into the network. (I have received multiple
invitations from people I hardly know, who appear unable to remove
3. Network inflation. Quantity pushes out quality. If someone has a
thousand contacts, I presume he doesn't know many of them very well,
probably hasn't even met half of them.
4. Duplication between networks. If I join multiple networks, I then
need to replicate my contacts on each network. (I have had invitations
from the same person to join his network on multiple networking
platforms - I cannot see that this makes sense to either of us.) There
seems to be no mechanism for federation between networks.
5, More radically, people are turning their back on networking - or at least being much more selective. Kirsten talks about Invitation Block. Seth Godin dismisses "It's not what you know it's who you know" as myth number ten. (For the purpose of these myths, see post on Protective Lies.)