Apple reported today that it had 300M iCloud users. Apple announced 250M iCloud users in January and 125M users in April of 2012. This means that it has grown by 20% users in 3 months.

This means that iCloud accounts for around 75% of the around 500M overall iOS devices sold so far, though many of those are not in use and some are too old to use iCloud.

Apple CEO Tim Cook announced in February 2012 that iCloud had over 100M users. In January 2012, he said that the service had 85M users. When Apple released iOS 6 late last year, it provided a significant boost to the numbers as it was the first version to take full advantage of over-the-air backup and restore.

iCloud has garnered both praise and criticism since its announcement, which is fair as it’s really two systems:

iCloud was launched in 2011 as a unification and expansion of Apple’s online syncing and data storage services like MobileMe. Since then, the service has grown massively in size. With a reported user base of 250M people, it’s one of the most-used cloud services anywhere in the world. But an enormous user base also means that any issues it encounters are writ large in the press and other forums….

There are really two iClouds, one that services Apple’s consumer services, and one that is offered up to developers to integrate into their apps.

One of them is used heavily inside Cupertino for its own services and the other is offered as a developer API and used only selectively for Apple’s own apps. I’m not here to say whether that’s right or wrong or fair or not or whatever, those are just the facts.

And, once you dig in, iCloud for developers is far less a completely holistic solution and much more of a loose bundle of networking protocols and systems that are unified in name only.

Still, iCloud’s sheer size makes it one of the biggest cloud systems in use by consumers today.

Image Credit: Mario Tama/Getty Images News

More to follow