DES MOINES, Iowa -- Even before Oprah Winfrey had left the building during the weekend's big campaign rallies for Barack Obama, the candidate's team had begun an intensive follow-up effort -- trying to turn tens of thousands of Oprah fans into Obama voters.
Celebrity endorsements are typically used by campaigns to draw large crowds and drive media coverage, but the Obama campaign is taking Winfrey's support to another level by trying to reach everyone who came to see her within 48 hours and get them on board.
It's especially important in Iowa, where the race is tight and just about 7,000 votes decided the winner in the last presidential caucus.
''This is going to be a margins election,'' said Democratic consultant Jenny Backus. ''This race is going to go to the campaign that finds new voters to bring into the process.''
At least 66,500 people attended the weekend Oprah-Obama rallies across three pivotal states, the Democratic presidential candidate's campaign said Monday. Admission didn't cost any money, but it wasn't free -- everyone who entered had to fill out a ticket stub with information on how they could be contacted.
As ticket stubs were collected at the Iowa events Saturday, they were sorted by geographical region. As the rallies ended, volunteer messengers braved icy roads to begin delivering stubs to the 35 offices across the state. Other stubs were scanned into image files and sent via computer.
The Obama campaign said 4,250 people pledged their time in order to get priority tickets to the rallies, agreeing to volunteer at least four hours so they could get a closer view of the Chicago talk show queen and her hometown senator.
In South Carolina, Obama's people said 68 percent of the nearly 30,000 people who showed up had never communicated with them before. Each person who entered the stadium for the rally was given a list of four phone numbers and first names along with a script for them to deliver in calls they should make asking for support in the upcoming primary.
Jamal Simmons, co-founder of cellular phone marketing firm Cherry Tree Mobile Media, said the calls and the campaign's pitch for audience members to sign up for text messages were smart innovations for a political campaign. He said, ''If they got half the people in that crowd to get out their phone and text message, they got 15,000 cell phone numbers that they can send texts to on Election Day telling them to vote, which is a pretty powerful tool.''
Steve Hildebrand, a top Obama strategist overseeing the effort, said the events Sunday in South Carolina and New Hampshire were followed by efforts similar to those in Iowa. Volunteers worked late into the night computerizing information from attendees and were able to print telephone call sheets the next day.
Hildebrand, sitting on a couch in the Des Moines office lobby to make way for all the volunteers working the desk phones, said Monday the goal was to put in a call to each of the attendees within 48 hours. Each person gets a thank-you for attending, some discussion of how inspiring the event was and is asked whether he or she will commit to voting for Obama and come in and volunteer. Those who live in Iowa are asked to attend a house party Thursday night near their home, and the callers have the local party address ready for anyone who might be interested.
Obama himself acknowledged that the impressive turnout for the rallies probably had more to do with Oprah than with him. But the campaign relished the chance to have him make his pitch to so many people.
''Getting people in front of Barack is the most beneficial thing we can do for the campaign,'' Hildebrand said. ''The most important aspect was to use it as an organizing tool.''
When asked Monday about Oprah's support, other presidential candidates played down the impact of celebrities in politics.
''I know that Oprah Winfrey sells a lot of books,'' said Republican John McCain, campaigning in South Carolina. ''I have the endorsement of four former secretaries of state. I would hope that carries some weight.''
''I don't think celebrity is going to sway them much,'' said Democrat John Edwards, who is bringing actors Kevin Bacon and Tim Robbins with him to Iowa later this week.
Democrat Joe Biden agreed that issues will determine the nominee during an appearance on ABC's ''This Week'' Sunday. But, he added, ''I'd love Oprah to be putting 15,000 people in a room for me to give me a chance to make my case to them.''
Stephanie Cutter, who was communications director for 2004 Democratic presidential nominee John Kerry, says the impact of the Oprah event is different from the concert Bruce Springsteen held in Madison, Wis., during the final days of that election. The Springsteen event drew an estimated 80,000 people, although unlike the Oprah event, no one knows for sure how many people were there since no tickets or personal information was collected.
''We estimated a good portion of them were new to the campaign and were hearing John Kerry for the first time,'' she said. ''The difference is we didn't sign those 80,000 people up to work for us in the Wisconsin general election. An endorsement is more than an endorsement when you're creating a field plan around it.''