With a support document updated today, Apple has informed users of iWork.com that the public beta of the service will be discontinued on July 31:
After July 31, 2012, you can no longer publish new documents to iWork.com from any iWork application on your Mac or iOS device. Documents already shared on iWork.com will not be available to you or to those you shared documents with.
Moving forward, you can use iCloud to share documents between your computer and your iPhone, iPad, or iPod touch.
Giving instructions to save documents already published on iWork.com, Apple is advising customers to start using iCloud instead. Currently, iCloud offers a functionality to store iWork documents online, and access them from the native iWork apps for iOS. With Mountain Lion, Apple will offer a new iCloud save interface, although it's not clear yet whether this will translate in a storage UI for iCloud.com as well, or an update to iWork for OS X. Currently, iCloud.com offers no sharing system for documents stored online, either.
Apple never showed too much interest in bringing new features to its iWork.com service, which has always been labelled as "beta" by the company. Some minor additions were brought to iWork.com last year, but the company never specifically mentioned major new functionalities would be introduced. Especially after the launch of iCloud, many had wondered if iWork.com was set to be discontinued, like other MobileMe services, and it now appears those doubts were legitimate, as the company is looking to move every document-related feature to iCloud. Right now, it's not clear whether native apps will gain new options for publishing and sharing, or if Apple will keep building more powerful web apps for storing and sharing documents online.
Apple has already confirmed that MobileMe will be discontinued later this year, on June 30.