Thinking more about the Kos controversy and the de-linking of his web site by the Kerry campaign I am reminded of the concept of the "common carrier".
(warning: arm-chair lawyer talk)
The "common carrier" was a legal principle developed to protect the telephone company form legal liability in the case where someone used a telephone to defame someone. The idea behind the principle is that a "common carrier" provides a service to useful to be derailed by the requirement that they monitor all the traffic on their system in order to watch for questionable activities. Now, in order to protect a providers "common carrier" status, they have to be very careful when it comes to stepping in and blocking the use of the service. For, if they block said use for one purpose, it could set the precedent that would result in them losing their "common carrier' status. In other words, if the phone company president doesn't like the fact that some people may be using his service to participate in phone sex and takes steps to block that, then he is essentially claiming responsibility for the content on his service and can therefore be held liable for other content which he personally does not object to.
In a way, this principle applies to political campaigns as well. The question comes down to this: are politicians responsible for all the actions of all of their supporters? There is no doubt that the Kerry campaign is benefiting from the open-ended structure of the blogosphere with its ability to inspire political activism and raising money. But with that comes the risk of being associated with amateurism and some real ugliness. Are the benefits to both the candidates and politics in general (along with the occasional ugliness comes a lot of good stuff from ordinary citizens and increased voter involvement (supposedly a good thing)) worth the occasional risks of someone letting lose with a wet-smelly one in public?
By de-linking Kos, the Kerry campaign has claimed a certain measure of responsibility over the behavior of their online supporters. They have set the precedent and they will be required to deal with the issue even more now that they have. Every time one of their online supporters does something questionable will they be required to de-link them as well lest they be accused of hypocrisy?
These are the kind of hoops that you are forced to jump through if you decide to take on the job of policing any portion of your base.
Democrats have it worse than Republicans in this respect because few people seriously hold the Republican leadership to account for the worst acts of their followers. Yet Democratic leaders are expected to grovel in submission any time some minor functionary is caught on tape saying something "out there". By their actions, the Kerry campaign has validated this mode of operation and they will have to pay the price for it in the future.