After Yahoo allegedly let government investigators scan millions of emails, privacy advocates are urging users to delete their accounts.

The digital rights group Fight for the Future launched its "Dump Yahoo" Wednesday, saying access the company provided US government officials was an unprecedented levels of surveillance and an unacceptable violation of privacy.

"We want to send a very clear message – Yahoo users trusted the company with their most sensitive information, and they were betrayed. And it is not OK," said Lizzy Jean of Fight for the Future, known for spearheading internet protests against National Security Agency surveillance and in support of net neutrality.

Reuters reported last week that Yahoo gave into classified US government demands to scan users' emails in 2015. In a follow up story, The New York Times outlined that Yahoo made it possible for investigators to search users' emails for a certain "signature," or unique identifier, that could surface messages originating from a "state-sponsored terrorist organization."

Key details about the surveillance tool – exactly how it worked, who built it, who had access to user emails, and others – remain unclear, and other tech companies have denied they're using similar tools. An Apple spokesperson told The Intercept the company "never received this type of request... . If we were to receive one, we would oppose it in court."

Sources told the Times that a Foreign Intelligence Surveillance Court judge authorized an individualized order to search emails for the digital signature. But rather than scanning only suspicious emails, Yahoo scanned all messages sent by its users, according to media reports. Motherboard reported the surveillance tool was similar to a "rootkit," a kind of software that gives attackers advanced eavesdropping capabilities.

Fight for the Future said its campaign is not just about convincing Yahoo users to ditch the company, but also to send a clear message to the tech community that this kind of secret surveillance won't go unanswered.

"The level of access that Yahoo granted the government goes far beyond anything we've ever seen in any other the previous surveillance orders that have come to light in recent years," said Jeff Lyon, chief technology officer at Fight for the Future. "This program was operated outside of any legal authority that we know to exist."

But it appears that despite extensive reporting about the program, much of the public remains unaware. A Wednesday poll from Morning Consult, a nonpartisan research company, found that 60 percent of 1,989 respondents heard "not much" or "nothing at all" regarding news about the surveillance program. Half of those surveyed said they viewed Yahoo's actions negatively, and 25 percent say it was good, citing national security concerns.

The Yahoo news immediately drew condemnation from many prominent voices.

I wonder how the candidates feel about Yahoo spying on every single customer's emails for NSA/FBI. Will they defend this shameful practice? — Edward Snowden (@Snowden) October 4, 2016

What #Yahoo is doing for #NSA is the email provider version of what the ISPs have been doing for years now. Maybe more people will care now? — Kevin Bankston (@KevinBankston) October 4, 2016

Requiring companies to spy on their customers is clearly unacceptable and unconstitutional. https://t.co/vpxu0duRXT — Bernie Sanders (@SenSanders) October 5, 2016

Well, in fairness. At least Yahoo finally got Search working. — Matthew Green (@matthew_d_green) October 4, 2016

The Dump Yahoo campaign comes just three weeks after the company announced hackers stole account information on at least 500 million user accounts in 2014 in what appears to be the largest theft of corporate data ever.

The hack was apparently enough to complicate Verizon's $4.8 billion purchase of Yahoo, though Verizon CEO Lowell McAdam said the deal will move forward in some form.