Yahoo is now notifying users when they are targeted by state-sponsored hackers.
Other companies, like Facebook, Google and Twitter, have had a similar policy for a while.
Twitter actually just warned a small number of users in early December that they may have been targeted by state-sponsored attacks. (Video via Twitter)
But none of these companies have revealed how they know when a government organization is behind an attack. Yahoo says it's staying quiet so the perpetrators don't learn its detection methods. (Video via Yahoo)
The goals of a breach can sometimes be hard to determine, but a cybersecurity expert tells MarketWatch state-sponsored hackers are usually trying to gain access to a corporate or government network.
If you aren't a corporate exec or government official but are connected to one, your account could be used to send malware to the real target.
In the blog post announcing the policy, Yahoo outlined several steps to improve the security of your accounts, such as enabling two-step verification or reviewing your recent activity in account settings.
This video includes images from Getty Images.