
Pick one?
"The change is currently only in the US and, at the moment at least, only on mobile devices. But in order to have access to its real-time feed Google is seemingly paying Twitter a standard flat licensing fee."
http://www.theregister.co.uk/2015/05/20/twitter_google_mobile_search_real_time_results/
"Twitter has crawled to Google to get Tweets displayed in the ad giant's search results once again. The micro-blabbing site previously had a deal with Mountain View to provide feeds of tweets directly within its search results."