Despite what might be happening in the lead-up to the 2012 U.S. Presidential election, there is one thing Americans agree on regardless of age, race, gender, or political party. They think 15-seconds is the acceptable amount of time to be required to view an online ad before they can access free content.According to a poll of a representative sample of Americans, Poll Position found that 54% of Americans think 15-seconds is the sweet spot for online advertisers and publishers to deliver ads without losing content views. Specifically, survey participants were asked, "When you go online to view free content, what do you think is the acceptable duration of an online advertisement you must view before seeing free content?" The breakdown of results is as follows:

• 54% believe 15 seconds is acceptable
• 12% believe 30 seconds is acceptable
• 4% believe 45 seconds is acceptable
• 3% believe 60 seconds is acceptable
• 27% have no opinion

Poll Position cross-tabulated the results by age, gender, race, and political party, and 15 seconds came out on top for every segment of the survey respondent audience (you can see the poll cross-tabs here).It's important to point out that 15-seconds was the shortest duration offered as a response to this poll. It's safe to assume that had 10-seconds, 5-seconds, and 0-seconds been included, the results would be more interesting. However, for authoritative content publishers, the results of this study are important. If you want people to see your content but also want to put a monetization barrier in front of that content, make sure that barrier is one that visitors are willing to accept and wait through.How many times have you been on a major media site, found a link to a video that looks interesting, clicked on that link, and been presented with a 30-second or 1-minute ad? It happens to me all the time, and you better believe I need to be extraordinarily interested in the video behind that monetization barrier or there is very little chance that I'm going to stick around. The publisher might make some money, but they've lost the chance to keep me on the site, further engage me, and improve long-term results.Of course, major media sites need to make money, and smaller publishers do, too. The trick is finding the right balance between monetization and continued visitor engagement. What's the opportunity cost of showing that 30-second ad before the clip of the cute kitten playing piano? Would a 15-second commercial deliver better all-around results? These are the questions publishers should be asking.With that said, the problem falls back on advertisers who prefer to keep costs low and simply repurpose ads from other media. Until advertisers realize that they'll get a better return on their investment by changing their ad content to match the online audience behaviors related to pre-roll video ads and other barriers to free content, publishers that need to make money from ads will still display those 30-second ads.What do you think? How long are you willing to watch an online ad before accessing content that you're lightly interested in? How about content you're heavily interested in?Here's my answer -- if I can Google the topic and get the information faster that way than watching a 30-second ad, you better believe I'm not going to watch that ad just to see the content behind it. 5-seconds, I'll definitely watch it. 10-seconds, I'll probably watch it. 15-seconds, I might or might not watch it. 30-seconds, I'll very rarely watch it. More than 30-seconds, forget it.Image: Flickr