Twitter has sold Yahoo its 'Firehose' - the full feed of public tweets - allowing Yahoo to integrate Twitter feeds into home pages, email accounts and search results.
"Through this arrangement, people will be able to find relevant tweets in Yahoo Search as well as other popular products and properties, including the Yahoo Homepage, Yahoo Mail, Yahoo Sports, and more," says Twitter founder Biz Stone.
"Yahoo will also be able to build unique Twitter clients into their properties, making it easier for folks to tweet wherever they feel comfortable within the Yahoo network."
Stone said he believes the deal represents a big opportunity, as tweets "have proven over and over again to contain valuable information". Users can judge this for themselves from today, although the other features are expected to kick in later this year.
"Let me try to capture the enormity of this integration in 140 characters or less: We’re turning the key to the online social universe–you will find the most personally relevant experiences through Yahoo," said Bryan Lamkin, senior vice president for consumer products at Yahoo.
"We’re also simplifying people’s lives by bringing their social worlds–and the world–together for easy access."
More usefully for Yahoo, perhaps, the deal means that people will be sending tweets without leaving the Yahoo sites.
Google and Microsoft already include Twitter updates in their search results.
Yahoo signed a deal with Facebook at the end of last year to allow Facebook users to view and send updates from Yahoo sites and put Flikr photos on Facebook.
Tweeters twitter on... and on...