Aaron Swartz and John Gruber have put together Markdown, another simplified text markup syntax. It’s cool, but I’m not too sure what differentiates it from the other simplified markup systems that have been released over the years (i.e., the age-old ReStructuredText, or Dean Allen’s Textile). (John says that the difference is that Markdown is a preprocessor, meaning that Markdown syntax can coexist with regular (X)HTML, and that may be legitimate; I can’t confess to having played enough with the alternatives to be able to recall how they deal with HTML.)

If nothing else, an interesting diversion, and another Movable Type plugin to play with a bit.