The Michael Jackson memorial service

Michael Jackson's memorial service on Tuesday drew 31.1 million total viewers across 18 broadcast and cable networks tallied by Nielsen.

Princess Diana's September 1997 funeral (which began at 6 am/ET), by comparison, drew 33.25 million viewers, while former President Ronald Reagan's June 2004 funeral (a midday service) had an audience of 20.8 million.

Check out photos of musicians who've died too young

As far as other daytime TV ratings milestones go, the November 1981 wedding of General Hospital's Luke and Laura was attended by 30 million viewers.

TV viewership only tells a fraction of the Jackson memorial story, however. The event also accounted for tens of millions of live streams online - 32 million alone from just MSNBC.com, ABCNews.com and FoxNews.com.

AEG, which produced the Staples Center event, estimates that all told, some 1 billion people worldwide watched the service in some manner. Such a grand total, however, perhaps never can be verified.

During Tuesday's prime-time hours, four different network newsmagazine specials — ABC's 20/20 and Primetime, CBS' 48 Hours Mystery, and NBC's Dateline — combined to deliver 26.2 million total viewers. By comparison, prime-time coverage of Reagan's burial drew 35 million viewers.