New numbers from comScore are speaking volumes about kids’ growing penchant for customizable digital play. User-generated gaming site Roblox has become the number-one destination for kids in the US in terms of daily visitors, total minutes, total page views and average visits.

The user-generated MMO, which allows its users to architect and share gaming worlds, experienced exponential growth in 2012, with players spending more than 176.3 million hours in game play – a 50% increase over 2011. Total page views for the website topped 13.3 billion, marking a 37% increase from 2011.

In terms of marketing, a full 86% of new Roblox users in 2012 came through word of mouth.

The Roblox marketplace, heavily comprised of eight-to 16-year olds, also captures kids’ desire to build and share digital assets. In-game items such as shirts and pants are traded to other members using a virtual currency – known as Robux. In 2012, more than 17.6 billion Robux were exchanged among users, which is equivalent to roughly US$176 million, a number that has increased by 150% since 2011.

The numbers speak to the growing influence of user-created content for both desktop and mobile devices (Roblox released a mobile app for iOS devices in July 2012).