Yahoo! has introduced Mail Web Service which will enable developers to connect to Yahoo! mail platform through SOAP or JSON-RPC. This follows closely after the announcement of unlimited email storage by Yahoo!

Yahoo! has announced that with the Yahoo! Mail Web Service, you can connect to the core mail platform to perform typical mailbox tasks for premium users such as list messages and folders, and compose and send messages…..In other words, developers outside of Yahoo! can now build mail tools or applications on the same infrastructure we use to build the highly-scaled Yahoo! Mail service that serves nearly 250 million Yahoo! Mail users today — users who might want to help you make some cash with your application.

Moreover, it will also enable developers to earn some money who will be entitled to referral commissions by building "compelling applications targeted at our premium email users." As per now, Yahoo! Mail is offering a commission of $10.00 for every new Yahoo! Mail Plus account referred by approved developers.