This morning, our old friends Omar Shahine and Mike Torres posted on the Inside SkyDrive blog with some new numbers related to SkyDrive, announcing that the service has reached 250 million users (the exact quote is “over 250 million people are now using SkyDrive”, implying but not explicitly stating that this refers to monthly active users).

Since the launch of Windows 8, SkyDrive has added some 50 million users.  SkyDrive is “built-in” to Windows 8, meaning that even using Microsoft’s latest Windows 8 figures from January, 1/6th of those licensees took the time to opt out (or decided against logging in to Windows 8 using a Microsoft account, or never actually installed the license in the first place).  That’s of course excluding all of the Windows 8 computers and licenses sold since January, and so the fraction is even bigger than that.

The blog post also points out another statistic from an April Official Microsoft blog post,  that there are now 700 million Microsoft accounts.  Using that figure, only about a third of them are using SkyDrive.  A significant number, for sure, but one with lots of room for growth, anyway.

So how does this compare to other “in the cloud” storage services?  As usual, there aren’t any hard numbers, but software management and security company OPSWAT, using figures obtained from their security and file uninstall software, has at least a ballpark figure, according to a market share report they released this April:

According to OPSWAT’s data (which admittedly could be wildly skewed depending on who actually downloads their software, take it with multiple grains of salt) SkyDrive brings up the rear among the four major backup sync products.  Dropbox holds a commanding lead, then Google Drive and Apple’s iCloud, and finally SkyDrive.  Actually, even “other” (an accumulation of several other services, all reporting less than 2% detection) beats SkyDrive.

Today’s numbers may actually tell us more about how sales are going for Windows 8, for Office 365, and for Office than they do about SkyDrive itself.  Adding 50 million users since last August, while being “built in” with Windows 8, and the default save location for Office 365 and Outlook.com, begins to sound like a much smaller number.  Only 50 million in 9 months, when Windows 8 has sold significantly more licenses than that, and you add in Office 365 and Outlook.com users too?

In January, Microsoft CEO Steve Ballmer dismissed Dropbox, saying “I’m not beating on Dropbox. They’re a fine little startup and that’s great.”, but the truth is that Dropbox continues to capture hearts and minds, and users of course, while Microsoft seems to be struggling to get even its most loyal users to use SkyDrive.

Don’t get us wrong, we think that SkyDrive is and always has been a great service, and the issue here may be more about the lack of any real data to compare services than about adding x number of million users.  How many SkyDrive users actively set up the service and actually drop files into SkyDrive, and retrieve them elsewhere, for example?  Are these new users mostly coming from Office 365, where SkyDrive is a default save location, and they may not even be aware that they’re using it?  Or is SkyDrive catching on, gaining ground on that “fine little startup” and turning heads with the new iOS app and new features?

What do you think about SkyDrive?  Do you use it exclusively, and how much?  Or do you use it in conjunction with Dropbox (or use Dropbox exclusively?).  Is it “catching on” among your friends, co-workers, and classmates?  Let us know in the comments.