Apple made the unusual move of spelling out the topics for its WWDC Keynote next week:

Apple CEO Steve Jobs and a team of Apple executives will kick off the company’s annual Worldwide Developers Conference (WWDC) with a keynote address on Monday, June 6 at 10:00 a.m. At the keynote, Apple will unveil its next generation software – Lion, the eighth major release of Mac OS X; iOS 5, the next version of Apple’s advanced mobile operating system which powers the iPad, iPhone and iPod touch; and iCloud, Apple’s upcoming cloud services offering.

Apple rarely — very rarely — tips its hand about keynotes and is generally even more tight-lipped about upcoming products and services. The only time I can recall them doing so is when they feel the need to manage rumors and keep a handle on expectations, which I think is what’s going on here. They want to emphasize that there will be no hardware announcements (read: no iPhone 5 or “4GS”).