Ruby Freeman, the mother of Shaye Moss and her former co-worker in the Fulton County elections office, has taken the witness stand.

Freeman introduced herself to the jury as "Lady Ruby" as questioning got underway.

Giuliani's unfounded claims about the two women prompted a deluge of threats that ultimately drove Freeman from her suburban Atlanta home, she told ABC News' Terry Moran in an exclusive interview last year.

Giuliani attorney Joseph Sibley scrutinized the credibility of the communications expert whose report on the reach of Giuliani's defamatory statements underpins the plaintiffs' request for tens of millions of dollars in damages.

Dr. Ashlee Humphreys, an expert witness for plaintiffs Ruby Freeman and Shaye Moss, fielded questions about the methodology she used to compile a report on the reputational harm that was done to the mother and daughter. Sibley sought to poke holes in that research as part of an effort to cast doubt on her findings.

"Reputation repair campaigns such as this are common," Humphreys said in response.

Sibley also highlighted Humphreys' participation as an expert witness in other cases, including in the defamation lawsuit filed against former President Trump by the writer E. Jean Carroll, and a case involving the conservative media outlet Gateway Pundit.

Noting that her past expert witness work exclusively targeted right-wing figures, Sibley asked, "Is there a reason for that?"

"No," she replied.

Communications expert Dr. Ashlee Humphreys, testifying for the plaintiffs, estimated that the cost to repair the reputations of Shaye Moss and Ruby Freeman is between $17.8 million and $47.4 million.

Humphreys said that her assessment found that Giuliani's defamatory statements about the two election workers had a "significant, negative and long-lasting" impact on Moss and Freeman's reputations.

"To repair reputational harm is not easy," Humphreys said.

A repair campaign for Moss and Freeman would include circulating statements in multiple media outlets, hiring influencers, and running media advertisements over a long period, Humphreys testified.

Dr. Ashlee Humphreys, an expert in sociology and communications, took the stand for the plaintiffs to testify about the reach of Giuliani's false election fraud claims online and on social media.

Humphreys said that prior to December 3, 2020, "there was practically no search traffic" for Ruby Freeman. After that day, Humphreys said there was a "dramatic increase over a period of months."

Humphreys said some of the search terms between December 2020 and January 2021 were "Ruby Freeman arrested," "Ruby Freeman fraud" and "Ruby Freeman FBI."

During her testimony, Humphreys walked through her analysis of the total number of times content had been displayed to uses, known as "impressions." Her impression analysis of several videos and posts by Giuliani and former President Trump included a Dec. 23, 2020, podcast in which Giuliani mentioned Moss and Freeman, which Humphreys said received between 584,855 to 807,751 impressions.

An advertising post by the Trump campaign that falsely claimed Freeman and Moss stuffed ballots in suitcases received between 8 million and 18.2 impressions, Humphreys said.

Some of the statements Humphreys said she found in her research were from Giuliani's "strategic communications plan" to challenge the election results, which included references to Moss and Freeman.

Judge Howell criticized key arguments presented at trial by Rudy Giuliani's attorney before jurors entered the courtroom this morning, reiterating her prior rulings that the former mayor's rhetoric about Ruby Freeman and Shaye Moss was "totally false."

Howell was responding to a last-ditch effort by Giuliani attorney Joseph Sibley to seek a ruling that plaintiffs had failed to meet the burden of proving their case, known as a Rule 50 motion.

Howell denied that motion, and in the process took aim at arguments core to Sibley's case -- as well as comments Giuliani had made outside of court.

"The powerful testimony of these Georgia officials demonstrated again and again and again" that those allegations were "totally false," Howell said of earlier testimony from two Georgia investigators that there was no evidence of election fraud.

Freeman and Moss organized "no highfalutin strategy like the one Giuliani" coordinated on behalf of former President Donald Trump, the judge added.

Howell took particular issue with Sibley's attempt to claim that no amount of money could change the mind of those who believe the 2020 election was stolen from Trump. Sibley compared them to "flat-Earthers," who believe, despite overwhelming evidence to the contrary, that the Earth is flat.