News of Facebook Inc.'s (FB) latest data scandal involving Cambridge Analytica has catapulted the social media giant and its founder and CEO Mark Zuckerberg to the center of rising concerns over how media companies manage and protect their users' data. The Menlo Park, California-based tech titan has seen an approximate $100 billion erased from its market capitalization in the recent week as analysts warn on momentum of a #DeleteFacebook campaign, joined by many, including Silicon Valley entrepreneur and investor Elon Musk. On Wednesday, the tech giant made a series of announcements, including statements that suggested that its data woes are much worse than previously thought. (See also: BofA Removes Facebook from Top Pick List.)

Facebook indicated that "malicious actors" took advantage of search tools on its platform which made it possible for them to discover the identities and collect information on most of its 2 billion users around the world. The company says it has now gotten rid of a feature that allowed users to let other users search for them by email address or phone number instead of name.

During a press briefing Wednesday, Facebook's CEO again personally apologized for his "huge mistake," in not properly considering how bad actors could abuse the social networking platform. While he took responsibility for a series of crisis plaguing his company, such as Russian interference in recent elections, fake news and the proliferation of other harmful content, Zuckerberg said will not step down from the helm. 

Malicious Actors Scraped Information

This week, Facebook also dropped news that the high profile Cambridge Analytica data scandal actually involved 87 million users, compared to previous reports which pegged the number of affected users at 50 million. Last month, news broke that the political consultancy had accessed information on tens of millions of Facebook users without their consent in order to help the Trump campaign with ads in the 2016 U.S. presidential race. Facebook suggests that Cambridge Analytica improperly gathered detailed information on 87 million individuals, including 71 million Americans. 

The abuse of Facebook's now-defunct search tools happened much more broadly and occurred over the course of several years. The company indicated that few were spared from the scam in which malicious hackers took email addresses and phone numbers from the "Dark Web" and used automated computer programs to feed them into Facebook's "search box" to find public information on its users. Hackers also reportedly abused Facebook's account-recovery function by pretending to be legitimate users who had forgotten details of their accounts. 

Congressional Hearings Set

"Given the scale and sophistication of the activity we’ve seen, we believe most people on Facebook could have had their public profile scraped," read a Facebook blog post Wednesday. 

Zuckerberg is expected to appear in Capitol Hill next week in a series of congressional hearings. Meanwhile, the Federal Trade Commission (FTC) has started an investigation into the company's data handling practices. 

"My hope is by the end of this year, we’ll have turned a corner on a lot of these issues and people see things are getting a lot better," said Facebook's 33-year-old CEO. (See also: 5 Reasons Facebook Is a Bargain.)