My colleague Robin Goad wrote about the rising popularity of Moshi Monsters in the UK, so I was curious to see how the website is performing in the US. Moshi Monsters offers visitors the chance to adopt a pet monster and take care of their monster by earning a virtual currency called ‘Rox’ through solving educational puzzles that test math, logic and vocabulary skills. The volume of visits to MoshiMonsters.com increased 23x within the Entertainment – Games category for the week ending March 20, 2010 as compared to the same week last year. In comparison, visits to Club Penguin increased 20% last week year-over-year while visits to Webkinz were down 41%.

Last week, Google was the highest referral source to MoshiMonsters.com, responsible for 24% of the upstream traffic to the website and 74% of those visits were from returning visitors (meaning visited the website in the past 30 days). The share of returning visitors from Facebook and YouTube, the 2nd and 3rd ranked websites for referrals were even higher at 82% and 86%, respectively.

As with the UK, the visitors to Moshi Monsters tend to be from affluent families that are likely be more willing to pay for a membership to use the website.