There is a very good resource for judges interested in evidence as evidenced (no pun intended) by this recent post By Evidence ProfBlogger:

Federal Rule of Evidence 606(b) generally provides that jurors are not allowed to impeach their verdict, but subsection (2)(A) provides an exception allowing jurors to testify that “extraneous prejudicial information was improperly brought to the jury’s attention.” A recent case out of the Sixth Circuit shows how social media searches can support a claim that this exception applies.

In United States v. Harris, 881 F.3d 945 (6th Cir. 2018), Talman Harris was convicted of one count of conspiracy to commit securities fraud or wire fraud,  one count of obstruction of justice, and three counts of wire fraud.

On September 6, 2016, Harris received a notification from LinkedIn that other LinkedIn members had recently viewed his LinkedIn profile. Harris opened this email the next day, after the jury had returned its verdict. Shortly thereafter, Harris discovered that one of the persons who viewed his profile was Christian Goleno, a student at Youngstown State University, located in the city where Harris’s trial was conducted. The record is inconclusive regarding the exact date Goleno viewed Harris’s profile, but the September 12, 2016 LinkedIn profile-views-summary page indicates that it was sometime between August 28 and September 12, 2016. Harris’s trial began on August 24, and the jury was discharged on September 7, 2016.

Thereafter, Harris

discovered that Goleno’s Facebook profile featured pictures of her and a juror from Harris’s trial, Juror Number 12 (“Juror 12”), and Juror 12’s profile featured pictures of Goleno. The voir dire transcript confirmed that Goleno was Juror 12’s live-in girlfriend. Goleno and Harris had no personal connection, and Harris’s trial had received little publicity. Thus, Harris concluded that Juror 12 must have discussed the trial with his girlfriend. Harris surmised that Goleno had probably searched his name on Google because his LinkedIn profile was on the first page of search results. Information regarding FINRA’s investigation of Harris, which led to his permanent bar from FINRA, was also on the first page of Google results. The government was precluded from presenting evidence of this investigation during Harris’s trial.

As a result, Harris moved for a hearing to determine whether Juror #12 was exposed to extraneous prejudicial information. While the district court denied the motion, the Sixth Circuit disagreed, concluding that

Harris presented credible evidence that Goleno found his LinkedIn profile, likely from searching for him on Google. The first page of Google results also included prejudicial information that the government was precluded from introducing at trial. Although the district court admonished the jury not to discuss the case with others, under the circumstances here, it is quite possible that Juror 12 told Goleno about the trial, leading her to Google Harris and to potentially communicate her findings to her live-in boyfriend, Juror 12.

Although Harris did not establish that Juror 12 was exposed to unauthorized communication, Harris did present a colorable claim of extraneous influence, which necessitated investigation.