While 33% of the most-engaging YouTube campaigns run under 30 seconds, only 11% of campaigns by volume run that length, per findings from a Yesmail Interactive study [download page] released in June 2012. And although YouTube campaigns rose sharply over the 3-month study period – by about 38% to 80 across all brands (3.5 campaigns per brand) – the average campaign engagement plummeted by roughly 66%. Yesmail’s actual engagement measure adjusts for follower size; rather than measure by sheer volume of Facebook Likes or YouTube views, actual engagement is a measure of individuals’ behavior. Thus one campaign may outnumber another in followers by 10 to 1, but its actual engagement may be far lower. Read the rest at MarketingCharts.