We'll tolerate 15 seconds for online ads Poll Position There may be 15 seconds of fame, but there's also 15 seconds of tolerance for an online ad. That's what a recent survey finds. On websites where content is free - no subscription or charge required - ad revenue is crucial to financially supporting a site. Just about everyone understands that. But there is a limit to patience when it comes to ads that play before a story or content is shared, a new survey from Poll Position finds. The organization polled 1,179 registered voters nationwide on Jan. 15. More than half, or 54 percent, say it's "acceptable" to have ads of 15 seconds. Longer ads were OK by some: 30 seconds was the limit for 12 percent, 45 seconds for 4 percent; and 60 seconds for 3 percent (the last group must be students of advertising or people with way, way too much time on their hands). Yet, 27 percent said they had no opinion on the matter. They either must be offline or busy streaming ad-free movies to their TVs.