Is Twitter set to usurp Facebook as the reigning social channel? New figures from GlobalWebIndex certainly suggest so.

According to the online consumer behaviour analysis company, Twitter may have already surpassed half a billion members, having grown by 83 million in just six months. GlobalWebIndex now estimates that one third of the active global internet population has a twitter account, accounting for a 40% leap in active users over the last six months.

Facebook, meanwhile, grew its active user base by 33% to 693 million during the same period, while Google+ saw an increase of 27.7% to 343 million active users (bumping it, allegedly, to second place for social networks in terms of active users, according to GlobalWebIndex).

This means Twitter is now the fastest growing social platform in the world, and amid reports that Facebook lost 600,000 UK users last month, it’s certainly on course to becoming the most popular, too.

This of course represents huge opportunities for brands, but as the GlobalWebIndex official blog post says, this does not come without challenges:

“We also need to consider the changing nature of usage. The growing interaction with brands makes customer service and staff interaction a must if Twitter is employed as a communication channel. Also, the growing usage of Twitter as a discovery tool means that content is absolutely critical for brands. Overall, content is the ever growing mega opportunity of the new social landscape.”