Live Blogging Apple’s iCloud Announcement

SAN FRANCISCO — Apple’s Worldwide Developers Conference is set to open here today at the Moscone Center West. The highlight will be the keynote address, by Steven P. Jobs, the company’s chief executive.

The conference is the yearly gathering for the companies that develop applications for Apple’s products. In an unusual preview, Apple has already announced that it will unveil new versions of the operating systems that run its computers, smartphones and tablets, as well as a new Internet service, iCloud.

I’ll be chronicling the events here as they happen, with contributions from John Markoff, veteran technology reporter. We’d like to hear any and all questions from readers, and will try to answer them in our coverage. Stay tuned for updates.Mr. Forstall says he will showcase 10 new features of the new operating system for mobile devices. First is a new "notifications" feature that makes it easier to see what's happened on the phone in one place. Android has a similar feature. When users visit the notification center, they can also see updates on wweather and stocks.

He also introduces a new section of the app store, Newstand, which lets people see all their subscriptions to newspapers and magazines in one place. The newstand service downloads new issues in the background.He also offers more details about the music sold through iTunes. Apple has sold 15 billion songs through its iTunes music store, which opened in 2003. My colleague Ben Sisario says that for those keeping score, that's a very quick jump in a short period of time. The last time Apple made such an announcement, in February 2010, the total was 10 billion. That means that in a little more than a year, the store has sold half as many songs as it had in the previous seven years.Mr. Forstall said Apple has sold more than 200 million iOS devices, or iPhones, iPads and iPod Touches. He says it is the No. 1 mobile operating system, with 44 percent of the market. He also updates iPad sales numbers, saying 25 million devices have been sold since it was introduced last year.After a short introduction in which Mr. Jobs talks about software as the "soul" of Apple's products, he introduces Phil Schiller, Apple's marketing chief, to show details about the new Macintosh operating system, Lion. There are apps going full screen in Lion, just as iPhoto could do before. There are also multitouch gestures that allow the new Mac OS to get rid of scrollbars.