Preliminary ratings are in for the second presidential debate, and it looks like it drew roughly as many television viewers as the first one did. According to TV By the Numbers:
"Coverage of the second Presidential Debate from 9-10:30 PM earned a 4.7 adults 18-49 rating on NBC, way up from a 3.2 fast national for the first debate on Wednesday, October 3. On ABC it scored a 2.8 versus a 3.0for the first debate. CBS garnered a 2.2, down from a 3.0 for the first debate. FOX notched a 1.7 compared to a 2.8 for the first debate. In other words, people generally stayed on whatever network they were watching at 8PM to watch the debate. More accurate debate numbers will be available this afternoon."
This gave NBC and ABC an advantage, as their popular shows "The Voice" and "Dancing With the Stars," respectively, brought big audiences to their debate coverage. The three broadcast networks plus Fox had about 38 million viewers between them. Adding in the rest of the cable networks, and allowing for the substantial adjustments characteristic of the final ratings for a major live event, should result in an audience comparable to the huge 67 million viewers for the first debate between Mitt Romney and Barack Obama.
Update: Final ratings from the A.C. Nielsen company put the audience for the second debate at 65.6 million people, which is just under the 67 million who watched the first debate.