Google policy indicates that people could lose control over content they store on the company's new "cloud" storage service, so they should read the terms carefully to determine if they're comfortable uploading files, an independent technology analyst in London, Ont., says.

The internet giant already mines data provided through email and other services to serve up ads that are specific to what people are doing online, and its updated terms of service announced in early March will now also apply to Google Drive, Carmi Levy told CBC News on Wednesday.

"[Google] wants to have a really good look at our information, to learn more about us, and then customize the online experience to us. That's pretty much what it's aiming at. It doesn't necessarily want to take that secret PowerPoint [file] that I've created for the future of my company and share it with the world," Levy said.

"But the thing is, the way the terms of use are written, it opens the door to that, and basically it means as soon as we put our stuff out there, we lose control over it. It opens up a very big Pandora's Box."

It's an issue that is moving into the spotlight as more and more consumer and corporate information moves into "the cloud," which basically means that it's stored online on third-party servers rather than direclty on local machines like personal computers, laptops and smartphones.

People are asking questions about the following section of Google's terms of service:

"When you upload or otherwise submit content to our Services, you give Google (and those we work with) a worldwide licence to use, host, store, reproduce, modify, create derivative works (such as those resulting from translations, adaptations or other changes we make so that your content works better with our Services), communicate, publish, publicly perform, publicly display and distribute such content."

It's a very broad set of permissions. What's more, the permission you give Google to use those files continues even if you stop using the services.

Meanwhile, another part of the same terms of service document states that, "Some of our Services allow you to submit content. You retain ownership of any intellectual property rights that you hold in that content. In short, what belongs to you stays yours."

This has generated debate over how the terms of service should be interpreted when it comes to the hold Google has on the data stored on Google Drive.

In contrast, Google Drive's established competitors, DropBox and Microsoft SkyDrive, make no direct ownership claims to user content in their terms of service.

"They basically say your stuff remains your stuff, and they do not make any claims to it," Levy said.

But critics point out that there are still grey areas in the terms of service for these and many other cloud-based services, and that users should read the terms carefully.

Adding to the questions surrounding what Google could actually do with Google Drive data, the company also has a blanket privacy policy that covers many of its products. Among other things, the policy on Google's website states that, "We do not share personal information with companies, organizations and individuals outside of Google unless ... we have your consent to do so. We require opt-in consent for the sharing of any sensitive personal information."

It adds, "If Google is involved in a merger, acquisition or asset sale, we will continue to ensure the confidentiality of any personal information and give affected users notice before personal information is transferred or becomes subject to a different privacy policy."

Meanwhile, the policy also notes that Google and those who manage the company's services may be allowed to view user account information. "If your Google Account is managed for you by a domain administrator (for example, for Google Apps users) then your domain administrator and resellers who provide user support to your organization will have access to your Google Account information (including your email and other data)." Among other things, it says the domain administrator may be able to "access or retain information stored as part of your account."

Critics have noted that part of the privacy issue around Google Drive springs from the fact that the company has privacy and terms of service agreements that cover many products and which use broad wording, rather than being written specifically for a given service.

The advice for users of cloud-based storage services is to have a clear understanding of privacy and ownership policies before storing sensitive or proprietary information online.