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 Beryl Howell, following a break, delivered a lengthy statement to jurors about details of the case -- including her determination that Rudy Giuliani has already been found liable for his defamatory comments.

Howell emphasized that the panel must assume that Giuliani failed to cooperate with his discovery requirements in the case in an effort to "artificially deflate" his net worth, and that jurors must understand that Giuliani benefitted financially from his defamatory comments about Freeman and Moss.

"Your job, ladies and gentlemen, is to determine the facts," Howell said.

Howell reminded jurors that their sole responsibility is to determine the damages associated with Giuliani's comments.

As Howell ticked through jury instructions, Giuliani intermittently shook his head and exchanged glances with his attorney.