While social media applications like Twitter and Facebook continue to battle allegations they engage in “viewpoint discrimination”, a bigger — arguably potentially much more disruptive — investigation is beginning to take shape, and Big Tech ought to be thinking of ways to tighten up.

While Google has been negotiating an investigation into their business practices from the Department of Justice, and Facebook has been the subject of a Federal Trade Commission antitrust investigation, it was announced last week that state 50 attorneys general from across the nation decided to launch their own antitrust investigation into Facebook.

Now comes word that legislators on the House of Representatives antitrust subcommittee, who have been investigating antitrust allegations related to potential anti-competitive behavior from Google, Apple, Amazon and Facebook, have ramped up their investigation and asked those companies to supply them with internal documents to aid in their work.

“Today’s document requests are an important milestone in this investigation as we work to obtain the information that our Members need to make this determination,” Rep. David Cicilline (D-R.I.), who chairs the subcommittee and is leading the antitrust investigation, said in a statement.

“We expect stakeholders to use this opportunity to provide information to the Committee to ensure that the Internet is an engine for opportunity for everyone, not just a select few gatekeepers.”

“This information is key in helping determine whether anticompetitive behavior is occurring, whether our antitrust enforcement agencies should investigate specific issues and whether or not our antitrust laws need improvement to better promote competition in the digital markets,” added Rep. Doug Collins (Ga.), the ranking Republican on the full Judiciary Committee.

Apparently one goal of the request is to bring to light dealings and processes these companies have previously jealously guarded as highly secretive.

The letter to Google parent company Alphabet, for instance, asks for records relating to “Google’s algorithm that determines the ranking of search results, including but not limited to how Google’s algorithm accounts for Google content or services and how Google’s algorithm accounts for non-Google content or services that compete with Google’s offerings.”

But the larger goal is to try to determine how these companies gained market power, if they used tools and business practices to discourage competition and market entry, and whether or not the market power they’ve enjoyed is actually harming consumers.

Free speech on social media may become a bit player in a much larger drama involving the relationship of Big tech companies with their users.