Facebook has shown that it cannot sail forever forward while facing various storms, including Cambridge Analytica and the Russian government's use of the social media platform to sow divisions amongst Americans during the 2016 presidential campaign.

As part of its second quarter of 2018 earnings announcement on Wednesday, the company trumpeted a huge jump in both year-over-year revenue (42 percent) and profit (31 percent).

But there has also been a notable slowdown in user growth. (Anyone recently delete their Facebook accounts?)

During a call on Wednesday afternoon, Facebook CFO David Wehner warned that investors should expect a slower rise. "Our total revenue growth rate decelerated approximately 7 percentage points in Q2 compared to Q1," he said. "Our total revenue growth rates will continue to decelerate in the second half of 2018, and we expect our revenue growth rates to decline by high single-digit percentages from prior quarters sequentially in both Q3 and Q4."

He added: "We are also giving people who use our services more choices around data privacy which may have an impact on our revenue growth."

Wall Street didn’t take too kindly to that: Facebook’s stock price dropped nearly 20 percent in after-hours trading.

Previously, since the announcement of the Cambridge Analytica debacle earlier this year, Facebook’s stock price had fallen but had, since, more than recovered.