why aren't there major players for a dedicated web based political campaign management platform?
Not for dearth of capital/ monetization risks .. if it were proved benficial, then politicians would be pumping money into the same.
For the last few years, social networking has tailored to a particular niche..
Linkedin- Jobs/career
Ning -private social networks
academia.edu - Social networking for Researchers
and so on.
If I had to manage a campaign, the closest solution I know of would be CiviCRM http://civicrm.org/