It looks like computer security experts were able to circumvent the first major programmed spawning of the Sobig.F virus by isolating the name servers it needed to propagate and taking them offline at the pre-programmed time (3pm ET).
On a more personal and practical level last night I saw Dave Winer whip up an instant filter for his email program by telling it to trash any messages with the words “See the attached file for details”. We had noticed that although the sender and subject lines on the Sobig-infected messages were ingeniously variable, each of the message texts was the same.
My university system administrators must have done something similar because after getting inundated with hundreds of See the attached file for details messages on Tuesday and Wednesday, there were only a few yesterday and none today, Woe to anyone who tries to use those six evil words to legitimate ends.
Anyway, here is an interesting article from the New York Times Technology about how the White Wizards who keep the net humming stopped the thing from spawing this afternoon.