Stupidity, is much like dark matter. It's everywhere, but you can't measure it directly. You can only detect it by its effect on things you can see.
I think anyone who can see can see Daily Kos has encountered a cluster of stupid.
Now before you get out your pointy fingers, let me try to convince you that the last thing you want to do it to try to identify the reservoir of stupid; you won't find it. The only solution is to add more smart. Let me explain how.
The equation is simple:
A. If you want to grow a movement in size and power, you want to look for converts.
B. If you want to destroy a movement and see it shrivel into irrelevance, you want to look for heretics.
Sites on the authoritarian right, like Red State and Free Republic patrol for heretics overtly. Say something unorthodox and you're banned instantly; sometimes your posts are deleted. That's the thing I've always loved about those sites: they will never create a netroots with any power because they are constantly thinning their own ranks.
We would never do that here. Unfortunately, we have a considerably more irritating approach to accomplishing the same thing: smug self-indulgence.
Everyone wants Daily Kos to be the place where they can grind their particular axe without any regard for shared purpose. There are scores of people at any time of day, ready to tell you why you aren't welcome here and why you are not needed because you don't appear to support their cause in exactly the way they want you to.
People are leaving because of this. They feel unwelcome. And that appears to be OK with the community. Consider it the I/P-ification of everything. Thankfully, there are some issues where consensus keeps the worst from flaring up: women's issues, gay rights and health care (more or less) are subject where the bullies are kept at bay by donut-wielding TUs.
Some people on the Internet are basically just looking for people to interact with. Some have donations to offer (money helps) and some will give their time and energy. I don't know what percentages are needed to make an effective "netroots," but it is clear to me that the population of Daily Kos is increasingly become just the first class: the social forum-dwellers.
Look, I've been flat-out told that I shouldn't be here by more than one person. I came here to "elect more and better Democrats," but if that's not important enough to Daily Kos to inspire some camaraderie, communication and understanding, then there are other places I can put my energy.
What's it going to be? Are we going to get along and attract converts, or are we going to drive away the heretics until Daily Kos is pure — and useless?