When will an unauthorized internet search make a jury verdict unsafe?

R. v. Farinacci, 2015 ONCA 392:

[51]       This problem has affected trials in many jurisdictions. As observed in R. v. Thompson [2010] EWCA Crim 1623, by the Court of Appeal, Criminal Division:

The use of the internet has expanded rapidly in recent years and it is to be expected that many, perhaps most, jurors, will be experienced in its use and will make habitual reference to it in daily life. It has already impacted on the court in cases such as R v Karakaya [2005] EWCA Crim 346, [2005] 2 Cr App R 77, R v Marshall [2007] EWCA Crim 35 and R v Thakrar [2008] EWCA Crim 2359, [2009] Crim LR 357; see also the experience in New Zealand, R v B [2008] NZCA 130, [2009] 1 NZLR 293. Just as it would in any other instance where it was satisfied that extraneous material had been introduced, the approach of this court is to make inquiries into the material. If, on examination, this material strikes at the fairness of the trial, because the jury has considered material adverse to the defendant with which he has had no or no proper opportunity to deal, the conviction is likely to be unsafe (R v Karakaya). If the material does not affect the safety of the conviction, the appeal will fail.