The Fortune 500 Business Blog Index, a much needed resource,  has launched — just in time to add to the book! (Note: it’s a wiki, so anyone can add updates to it.) The index is the result of a joint effort between Chris Anderson and Wired and Ross Mayfield of Socialtext. Learn more from Chris, writing here on his Longtail blog. According to the calculations of Wired’s interns, only 16 members or 3% of the Fortune 500 have blogs. You can download the Fortune 500 blogging spreadsheet they created.

Chris’s theory, which hatched during a dinner with Doc Searls, is as follows:

“Perhaps, Doc wondered, the risks and uncertainties of public business
blogging are so great that big companies only do it under duress, when
their other corporate messaging has lost traction. So companies on the
way up don’t want to mess with their success by introducing a new lens
on the enterprise that isn’t controlled by the PR department. But
companies on the way down are willing to try anything to regain the
confidence of their customers.”

And the evidence thus far, after an initial look at the Fortune 500 blogging index:

“(We) found only 16 members (3%) of the Fortune 500 with business blogs.
And, for what it’s worth with such a small sample size, the average
trailing 12-month share performance of the blogging members was +5.7%,
while the non-blogging members was +19%. So although the statistics
aren’t good enough to confirm Doc’s theory, they do point in the right
direction.”

And the 16 Fortune 500 bloggers are:

Amazon, Avaya, Avon, Cisco, Dell, EDS, Ford, GM, HP, Microsoft, Motorala, Oracle, Sprint, Sun, Texas Instruments and Boeing.

[via Jim Turner]