Facebook's devastating earnings report marked the end of a difficult year for the company, which has been battered by whistleblower allegations, a major global service outage, and protests and controversy over its policies. 

Facebook reported on Wednesday that daily logins to its services dropped nearly 500,000 during the last three months of 2021, the first time in the company's 18-year history that user activity has declined.

It sent Facebook shares plunging 26 percent as of Thursday when the markets closed, wiping more than $230 billion off the company's market cap and erasing at least $29 billion from CEO Mark Zuckerberg's net worth. 

Zuckerberg blamed the dismal performance on Apple's privacy changes and increased competition from services such as Tik Tok, but the decline in user activity follows a year of notably bad PR for Facebook.

Perhaps most significantly, former Facebook employee Frances Haugen leaked thousands of internal documents and embarked on a world tour testifying with damaging allegations against the company.

Among the allegations were that Facebook is aware of the negative impact that Instagram has on teen girls, and that the company contributes to violence in developing countries. 

Other claims based on the leaked documents relate to Facebook's role in spreading false or divisive information. 

Haugen has kept up the pressure, appearing on Thursday before a parliamentary committee in Australia to claim that Facebook underinvests in safety measures on its platforms Down Under.

She said Facebook disproportionately spends its safety budget in the United States and as a result the rest of the world misses out.