As consumers, we sometimes ignore advertising as much as we can. Other times, we can't get enough--such as when the best spots air during big events such as the Super Bowl, or now the 2012 London Olympics, which kick off in just a few days.

You may not be able to afford a prime-time ad spot in the middle of the Olympics, but you can always learn what other brands are doing well.

The first, second, and third spots--in terms of which official Olympic sponsors are stirring up the most social-media buzz--are filled by P&G, EDF Energy, and Samsung. I know this because social-video platform Unruly Media has created an interactive infographic that measures which spots are getting the most shares on social networks.

Along with it, Unruly COO and co-founder Sarah Wood posted a video in which she discusses the factors that go into creating a spot that will ignite conversation across the Web. (I included Wood on my Women to Watch list earlier this year.)

"Academic studies have shown that intense emotional arousal is a key factor in the sharability of video content," she says. "And to maximize the spreadibility of content, it should resonate within a broader cultural context, too."

Enter Exhibit One: The current winner of the social-sharing race--P&G's nod to mothers around the world and the athletes they spent years supporting. Though I can't say how fathers will react, I guarantee that if you're a mother, this one will pull on your heartstrings, regardless of which country you're rooting for.

EDF Energy is No. 2 in the race, mostly I'd guess because of Zingy, the cute little robotic mascot it features in a couple of its most popular videos.

Cute, it turns out, is another feature of videos that people like to share, Wood says. Other descriptors that increase engagement include videos that are funny, shocking, moving, and hot, with the latter definitely present in this one (check out all those long, toned legs!).

Wood says videos that are random, unbelievable, zeitgeisty, controversial, or illuminating also inspire people to share them.

This one is in third place, and what could be more zeitgeisty and unbelievable than a commercial from Samsung in which David Beckham plays Beethoven's "Ode to Joy" with soccer balls after choreographing the number on a Galaxy Note? This one's a little hot, too.

All of these videos are getting tremendous action, which is different from Olympics past, Wood says. However, the three top videos from Beijing 2008, which received only tens of thousands of views back then, have tripled their share counts in the past two weeks.

"I think what this suggests is social video doesn't just have a limited time frame, but if you get the content right, you can create content that has a much longer-lasting effect that people can still be talking about years ahead," she says.