The global social media landscape continues to shift in surprising ways. Two new Forrester reports show – as expected – a continuing rise in social media usage, but there is no substantial growth in social media-inspired content-creation. Meanwhile, we note another significant (though hardly surprising) development, as Twitter overtakes MySpace in unique visitors.

The Forrester reports – which drew data from 275,000 consumers globally – show a significant jump in the number of people joining social networking sites around the world: 11% in Europe, 18% in metro China, 11% in Australia, and 8% in North America.

However, between 2009 and 2010, no markets showed growth in the number of people who create social content – those who blog, upload videos or photos, etc. Commenting on the Forrester statistics, consumer insight analyst Jackie Anderson notes: “The initial wave of consumers using social technologies in the US has halted. Companies will now need to devise strategies to extend social applications past the early adopters.”

These shifting trends in social media content creation are highlighted just as Twitter hits another milestone – passing Rupert Murdoch’s MySpace to effectively become, as the Wall Street Journal puts it, the world’s third-biggest social networking site.

For those keen to watch the trends in social media – and that probably ought to mean most people in business – these are interesting times as the sector faces its first tough questions about whether there is enough intellectual and creative brainpower among social networkers to attract the next wave of followers.