Well that was fast. A little over a week since we posted the blog about the viral success of the Old Spice “Smell Like a Man” YouTube campaign, the numbers that really matter are in…and they’re good. Nielsen is reporting that Old Spice has seen a 107% increase in sales in the last month along with a 55% increase in the last three months. That’s fantastic for any marketing campaign, but it’s remarkable for a campaign that lives mostly on the web as YouTube videos. If this doesn’t justify the use of viral marketing and social media in your marketing plan, we’re not sure what will.