This isn’t an app story, per se – it concerns web-based virtual world Habbo Hotel – but it’s a cautionary tale for any app developers looking to make social apps for a younger audience. Habbo has been going for a long time, and the avatar-based world is hugely popular among its audience of children – 268m registered users with 3m more joining a month. However, tonight it’s expected to be the focus of a Channel 4 documentary alleging that paedophiles have been frequenting the site and trying to groom kids, and also claiming that sexually explicit material (although this appears to be text chat rather than anything else) is rife. Investor Balderton Capital has already pulled its backing from Habbo, returning its shares at zero value, as a result of the investigation.