Web search

A web search API key is available, for access to Yahoo! BOSS web search results, typically used to detect copyright violations (copyvios).

It was bought by the Wikimedia Foundation since bugzilla:32816 and you should probably ask it to mw:User:MPelletier (WMF) if you want to run a bot or service for Wikimedia projects, though he's not "in charge" of it. It's used e.g. by m:w:en:User:EarwigBot/Copyvios and perhaps by m:w:en:User:CorenSearchBot, m:w:en:User:MadmanBot; nobody else is known to have succeeded in getting access. Such search queries used to be used a lot (especially via mw:Manual:Pywikipediabot/copyright.py) before pricing policies by search engines changed (around 2011).