Even before MacWorld opened its doors Monday morning, the sharp-eyed bloggers at Valleywag had spotted the banner and put forward a smart theory.

FORBES: Channeling Steve Jobs

This research, published recently in Physical Review Letters, supports a theory put forward several years ago by John Abrahamson, a chemical engineer from the University of Canterbury, in New Zealand.

ECONOMIST: Ball lightning

There is a controversial theory put forward by economist Steven Levitt that the increased availability of legal abortion after the Supreme Court ruling in 1973 on Roe v Wade meant that fewer children were born to young, poor, single mothers.

BBC: US crime figures: Why the drop?