JSON
Javascript Object Notation
Developed by Douglas Crockford, of Javascript: The Good Parts fame
Hip alternative to XML for data sharing.
Example: http://www.archive.org/details/uso20110129?output=json
Consider: https://addons.mozilla.org/en-US/firefox/addon/jsonview/
Commandline
jq is a nice command-line tool for JSON parsing on the command-line.