When you've lost Star Trek actor Wil Wheaton, you know you're in trouble.

Users including Wheaton are peeved at cloud note-taking service Evernote following an update to its privacy policy giving employees the right to read users' information in order to improve its machine learning algorithms.

The latest update to Evernote's privacy policy allows some of its employees to "exercise oversight of machine learning technologies applied to account content, subject to the limits described below, for the purposes of developing and improving the Evernote service."

"This is primarily to make sure that our machine learning technologies are working correctly, in order to surface the most relevant content and features to you," Evernote says. "While our computer systems do a pretty good job, sometimes a limited amount of human review is simply unavoidable in order to make sure everything is working exactly as it should."

To protect users, Evernote "strictly limit[s] the number of Evernote employees who have access to user data to those who need this access" to perform functions it lists in its privacy policy. Those employees are subject to background checks, and "specific security and privacy training at least annually to ensure they are up to date on the latest privacy and security requirements and standards," Evernote says.

Evernote's assurances weren't good enough for some users.

"Time to uninstall Evernote. Like, right now," says Wheaton on Twitter.

"Yeah, I love Evernote but this pretty much does it for me," says "SurlyDave" on reddit.com/r/evernote. "The suggestion that if I don't consent to someone reading my notes I won't have access to future upgrades means I'll be looking elsewhere for a similar product. Shame, because I really use Evernote a lot and moving my data across will be a big hassle."

"You are uploading stuff to the cloud, assume you have ZERO privacy," says ryanmercer, who adds that users seeking privacy should look for a service that complies with the US Health Insurance Portability and Accountability Act.

We contacted Evernote about this, and a spokesman said the company is working on a statement about the issue.

Evernote says users can use encryption on its desktop clients to protect data. Users can also opt out of the machine learning feature, which will also stop Evernote employees accessing data to improve machine learning.

Previously, Evernote's privacy policy provided for disclosure of information for reasons including investigating potential terms of service violations, preventing or taking action against illegal activities, and compliance with court orders and subpoenas. This is standard for cloud services.

Machine learning is strategic to Evernote. Part of the company's reason for an ambitious migration to the Google Cloud Platform from Evernote's own private cloud was to get access to Google's machine learning services. (See Why the Evernote Elephant Packed Its Trunk for Google Cloud.)

Want to know more about the cloud? Visit Light Reading Enterprise Cloud.

Evernote has had a tumultuous history. In 2012, the company became one of Silicon Valley's first so-called "unicorns" -- privately held companies with value of more than $1 billion. The company cut 13% of its staff last year, or 47 employees, and longtime CEO Phil Libin resigned.

Evernote is looking to transition from a consumer service with a free plan used by a big base of users, as well as some paid plans, to a paid subscription service used by professionals. While it still offers a free plan, Evernote has cut back on its capabilities and raised prices, angering its users. This month, the company opened a new engineering office in San Diego. The last thing Evernote needs is a black mark for failing to protect customer data.

As for me: This new privacy policy from Evernote is a concern. I use Evernote extensively for personal and professional business, including to store article notes and research. I'm not much concerned about my private data, but, as a business journalist, I have a responsibility to safeguard the confidential information that's entrusted to me. I'll be watching developments closely to see if Evernote is a service I want to stick with.

— Mitch Wagner, , Editor, Light Reading Enterprise Cloud