Our individual outreach efforts increase in scope and intensity when we start feeling insecure about our jobs. In the current economic context, feeling some level of stress about job security is natural. My hypothesis is that the fact that Twitter suddenly took off and reached a tipping point is related to the fact that people are reaching out, trying to connect or reconnect, gather job intel, learn about a new field, etc... either because they've already lost their job or because they feel they might be next.
I am not suggesting that Twitter's success would not have happened without the economic crisis. I'm only suggesting that the economic crisis gave it a push over the tipping point. What do you think?
You could also argue that Twitter is the cause of the economic crisis.... (Economist Blames Twitter for Downturn), but I won't do that!