On his blog, Marc Andreessen recently announced that Ning has officially surpassed 200,000 social networks hosted by the service, continuing at a torrid pace. Pretty impressive. But how long will it continue?

Ning added the second half of that 200K since September of 2007, i.e. over the last 6 months. This is a prediction that Ning will pass 300K social networks by the end of the year, i.e. 8.5 months now.

This is a difficult prediction to make, because Andreessen is known to hold the company's metrics pretty closely. If by the date of expiry no announcement has yet been made, all efforts will be made to contact Andreessen and co. for the neccessary information. However, it can generally be assumed that the company would happily announce the 300K milestone, so absent of any public metrics, the lack of an announcement of 300K social networks by the end of the year will lead the editors to judge the prediction unfavorably.