The Salsa Commons API is a REST and XML API that, as Salsa explains,
"At it's simplest, using the Salsa API may consist of just a form placed on an external website ... At it's most complex, you could use a Ruby library to authenticate, pull down information on recent supporters and events, validate that data, change it, and submit it back to the node, while generating and displaying counts of petition signers -- all through the API."
As far as web search tools go, few have generated as much hype as Wolfram Alpha. The service, which bills itself as a "computational knowledge engine," differs from search engines such as Google, in that it does not return lists of web pages. Rather, Wolfram Alpha attempts to calculate answers to user queries. For example, a query of "los angeles county median household income" will return the result "$43,518."