Aside from the disgusting content on sites such as DU and Kos, the sites are poorly implemented from a technical aspect. The HTML never survives a validaition suite (unlike JR's superb, clean code here on FR).
There's so much clutter and needless JavaScript over there on the cited leftist sites that load times before a page is rendered is unbearable in itself.
Long before I ever joined the patriots here (when I still had dialup service at a blazing 9600 BPS) at Free Republic earlier this year, FR was my goto site for fast-breaking news and intelligent commentary. In addiiton to the superior content here, the look and feel (along with the uncluttered appearance with speedy page rendering), Free Republic is greatness based on technical merits alone.
The Ubuntu of political websites.