Hitwise reports that its monitoring of a Tide an ad-supported viral campaign - where visitors to a special website can sign up for free samples and recommend the site to friends - increased Tide.com's share of visits by a factor of nine for the week ending January 22. The next week jumped up a further three times, presumably as the viral effect kicked in. Evidence for this showed up in the fact that more than half of those latter visited came from email service referral links.