I just don't get why the American left is just so fucking stupid about this. It's staring you right in the face.
[WS:] I do not think they are stupid about this. It is just that the networks that they used to use disappeared, and they had to replace it with something else. The problem was that there was not much to choose from. The only institutions capable of creating and sustaining networks on a large scale are the academia, the military, and organized religion.
The left has been using social networks created by the academia, as the other ones are not very conducive to left politics. However, academic networks have limitations - they tend disintegrate when people more to the "real life" and become concerned with raising a family, making a living, paying bills, etc. As a consequence, the left has been confined to the are where this type of networks remains the strongest - the academia itself.
The suggestion to use progressive religious networks is a good one, but certainly not panacea. Using them may increase the influence of the left somewhat, but do not expect miracles. Even in countries with traditionally strong left social networks, left parties are in the minority. So if the left can muster 10% of the votes on a national scale, it would be a huge success.
Somebody on this list mention local focus in left organizing, and that seems like a good idea. It will certainly maximize the influence of the left. Democrats have already sensed that and concentrate only on those areas where they can win, while passing over those where their chances are minimal. This basically translates to "fuck the South" approach - but that is a sad reality of the US political landscape.
Wojtek