A fascinating photo from WordPress chief Matt Mullenweg's keynote address at last weekend's WordCamp in San Francisco revealed a list of (US) 'government agencies using WordPress':

So that's all the armed services, NSA, CIA and FBI... which kind of puts the '(in)security' argument in some context. Hey, the Marine Corps love it so much, they're listed twice! But no reference to 10 Downing Street, that I've seen reported anyway. Whassup Matt, no love for the UK? Ah well, it's good to know that we're not alone.