A source familiar with Facebook's prepared testimony for the Senate Judiciary Committee tomorrow says the company will disclose that over the course of three years, approximately 29 million people were "delivered" or "served" content from pages related to the Internet Research Agency (IRA) – the Russian troll farm associated with the fake campaign ads.

Thanks to sharing and engagement, however, up to 126 million people could have seen this content over the course of three years.

Some key context – because people's news feeds are filled with all kinds of information all day long -- an IRA-related ad may have been one of 28 thousand pieces of content that flowed through people's news feeds during that three-year time period. Facebook will likely say the Russian ads were essentially a drop in the bucket in terms of all the content people viewed on a daily, weekly or yearly basis.

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Meanwhile, a source familiar with the testimony being offered by Twitter to Congress in the similar hearing, says that the social media platform connected the 201 accounts they identified with Congressional investigators to broader Russian election-focused activity on Twitter, including the full set of 2,752 accounts that we now believe are associated with the Internet Research Agency or IRA.

All 2,752 accounts have been suspended and Twitter is now "proactively giving committee investigators the handles of these accounts, and we have taken steps to block future registrations related to these accounts-- and we have pledged to Congress that we will inform them as we uncover more related accounts" according to the source.

They also claim that election-related Tweets generated by Russian-linked, automated accounts constituted less than three quarters of a percent (0.74%) of the overall election-related Tweets on Twitter at the time.

Tech giants Facebook, Twitter and Google will all testify before Congress about Russian disinformation Tuesday and Wednesday.

CBS News' Andres Triay contributed to this report.