Facebook is enmeshed in several investigations into Russia’s interference in the 2016 election. Details continue to emerge about the 3,000 political ads linked to Russian actors that it sold and ran during the 2016 election cycle. It's now handed those ads over to congressional investigators, as well as special investigator Robert Mueller, and will join representatives from Twitter and Google parent company Alphabet at a House Intelligence Committee hearing on Nov.1. The constantly evolving story of how the social-networking giant found itself at the center of all of this, and, crucially, what that could mean for President Trump, can easily get confused amid competing headlines around healthcare, hurricanes, and an escalating nuclear standoff with North Korea.

To help, we’re here to walk you through everything we know---and don’t know---about Facebook’s role in the 2016 election and the subsequent investigations. We’ll update this list of questions and answers as we learn more.

What did Facebook give investigators?

In early September, Facebook said it had identified $150,000 of political ads purchased by fake accounts linked to Russia. It attributed about $100,000 of the total, or 3,000 ads, to 470 accounts related to a Russian propaganda group called Internet Research Agency. It found another 2,000 ads worth $50,000 by searching for ads purchased through US internet addresses whose accounts were set to the Russian language. The ads touched on hot-button social issues such as immigration and LGBT rights, as well as content aimed at stoking racial resentment against blacks and Muslims. About 25 percent of the ads geographically targeted certain regions of the United States. The majority of these ads ran in 2015. On Sept. 21, Facebook confirmed it had shared the ads with Mueller's team and would do the same with congressional investigators.

How many people did the ads reach?

In an Oct. 2 blog post, Facebook said roughly 10 million people saw the ads and that 44 percent of those impressions took place before the election. Considering that fewer than 80,000 votes cost Hillary Clinton the election, that number is intriguing. And researchers have since pointed out that the fake accounts that purchased those ads likely reached even more users through old-fashioned viral posts.

According to Jonathan Albright, research director of the Tow Center for Digital Journalism at Columbia University, organic content posted by just six of the 470 fake accounts Facebook pinpointed may have been shared 340 million times. Albright used the social-media-monitoring app CrowdTangle to analyze traffic to several of the now-deleted accounts that have been made public, including one page called Blacktivists and another called Muslim America. Those same posts received roughly 19.1 million interactions in the form of people clicking the "like" or "share" buttons.

These numbers dwarf the 10 million figure Facebook has provided. That's because Facebook is only accounting for the reach of ads paid for by a Russia-linked troll farm. The reach of the viral content those same trolls posted is far wider---and tougher to catch. Unlike ads, viral content leaves no money trail.

How did Facebook find these ads?

The only detail Facebook has shared publicly is that it looked for US internet addresses set to the Russian language, then “fanned out” from there, as a Facebook spokesperson told WIRED. That makes it impossible to know whether Facebook has identified all suspect ads or just those the Russians were laziest about hiding.

It’s likely, however, that Facebook's search has not covered everything. On Sept. 21, during a Facebook Live address, CEO Mark Zuckerberg admitted as much, saying, "We may find more, and if we do, we will continue to work with the government." We know, for instance, that Internet Research Agency, the propaganda group, has officially shut down. But similar firms, including one called Glavset, operate with the same people at the same addresses. The Facebook spokesperson would not discuss whether its investigation would have caught these other shell companies.

What changes has Facebook announced, and will they make a difference?