NEW YORK (AP) -- Barack Obama apparently isn't the only "rock star" in presidential politics this year.
After days of intense media coverage about Republican vice presidential candidate Sarah Palin's qualifications, more than 40 million Americans tuned in Wednesday to see for themselves what they thought of her.
The huge audience for Palin's acceptance speech rivaled that for Obama's address at the Democratic National Convention six days earlier, and set a tough standard for the top of her own ticket. John McCain was to accept the GOP presidential nomination on Thursday.
The first two days of the GOP convention essentially served as a build-up for Palin. The Alaska governor hadn't spoken publicly since McCain selected her for the ticket last Friday, as a series of stories circulated questioning whether McCain had properly vetted her.
Her poised speech, primarily going after Obama and touting McCain's case for the presidency, was gushed over by many analysts.
An audience of 37.2 million people watched Palin on ABC, CBS, NBC, CNN, Fox News Channel and MSNBC, Nielsen Media Research said Thursday. PBS estimated its audience at 3.9 million, based on a less reliable sample of several big cities. Nielsen does not count the audience for C-SPAN, which also showed the speech.
Last week, Nielsen said 38.4 million people watched Obama speak at a Denver stadium on the six commercial networks, along with BET, TV One, Univision and Telemundo - four networks that didn't cover Palin's speech. PBS added an estimated 4 million to that total.
Nearly 2 million more women were watching Palin than men, Nielsen said.
Viewers were far more interested in Palin than Democratic vice presidential candidate Joe Biden. Biden's speech to Democrats last week was seen by an estimated 24 million people.
The audiences for the Obama and Palin speeches were bigger than the ones this year for the Academy Awards, the finale of "American Idol" or the Olympics opening ceremony in Beijing.
Nearly 120 million Americans voted in the 2004 presidential election and numbers could be higher this year because of young and minority voters attracted to Obama, and renewed enthusiasm among Republicans for their ticket.
Fox News Channel led the way Wednesday, with 9.2 million people watching Palin's speech on the cable channel. It was the third-largest audience in its history, behind only President Bush's speech on Iraq in March 2003 and a Bush-Kerry presidential debate in 2004.
For each night of the GOP convention so far, Fox's audience has been bigger than any of the other cable or broadcast networks. That duplicates a feat accomplished at the 2004 Republican convention for Fox, the first time a cable network had outdrawn broadcasters for a major news event.
NBC had 7.7 million viewers for Palin's speech, followed in order by CNN, ABC, CBS and MSNBC, Nielsen said.