In these challenging times, they have become an escapist's dream. Online subscription computer games allow players to control a character - or 'avatar' in the parlance - explore the landscape, fight monsters and complete quests. Players can study for professions such as tailoring, mining, cooking and first-aid, while characters can form or join guilds and clubs.

Activision Blizzard's World of Warcraft has taken the gaming world by storm, making its creator the most successful gaming studio, with 11m paying subscribers worldwide and revenues topping $1.34bn (