The news comes as the NSPCC released the results of a poll, which found 75 per cent of children had seen images on the net that disturbed them.
Californian-based Yoursphere Media has handed a six-figure account to Bright Young Things Communications.
The 12-month account was won following a two-way tussle between Bright Young Things and Weber Shandwick.
The site says it is the only one in the world to comply with the all the recommendations made in the influential Byron Report, which was released by the Government in March and contained proposals on how to improve child safety online.
Bright Young Things founder and MD Niall Cowley said: 'It is different to existing networks, because it identifies the user and fosters accountability. If you don't have anonymity, you'll be less likely to misbehave.'
Bright Young Things was set up by Cowley, the former comms director for Beatbullying, in March. It will handle all comms for the site in the UK and Ireland, from press office work to campaigns.
Yoursphere, which is aimed at nine- to 17-year-olds, was launched in the US in July. Here, it will be launched to an 'inner circle' of children and stakeholders in December. The main public launch will take place in February 2009.
Yoursphere president Mary Kay Hoal said it was important for the site to offer young people 'the safest online community that authentically reflects their interests and aspirations'.
Bright Young Things hired Lexis PR account director Louise Stoddard as associate director client services in September (PRWeek, 26 September).