Often when others join the party and he has something to say about their implementation or contribution he will say it in a pretty direct manner. This has led to some interesting spats. Some that come to mind:
RSS vs ATOM
Harsh/sarcastic words and criticism by Mark Pilgrim (dive into python guy)
Aaron Swartz wrote a service to watch for edits in Dave's blogs posts a long time ago to see if he was chaining "history."
Finally, just scroll down on this page you will see that the general reaction seems to be more negative than usual. A lot of time resorting to personal attacks.
For those of you who don't know his writing he has stuff online back to '95 or maybe earlier and it would serve the younger techies well to go back and take a look with an open mind.