Google+ took a mere 16 days to hit 10 million users. By comparison, both Twitter and Facebook took over 2 years to hit that milestone, requiring 780 days and 852 days respectively.

Leon Håland has kindly put together this graph, which helps put Google+’s hockey-stick growth into perspective, compared to its social networking counterparts:

GGraph Google+ reached 10m users in 16 days. Want to know how long it took Facebook and Twitter?Whilst there’s little doubt that Google+’s growth is impressive, it’s probably also worth noting that it did have a considerable head-start on both Twitter and Facebook, which were both starting from scratch – as a social network, as a brand…as everything.

Google, on the other hand, has thirteen years’ growth behind it and is one of the most recognizable digital brands in the world. It already had a mammoth user-base across its plethora of products, so it’s perhaps not all that surprising that it could notch up 10m users in around a fortnight.

Google+ is thought to have reached the 10 million users mark around the 13th of July, and it had doubled-up again by about a week later. That’s 20 million users in three weeks.

Google’s latest attempt at creating a social network seems to be paying off, and it has so far received pretty favorable reviews. The Next Web carried out a quick survey of our readers in early July, and we found that two-thirds of users preferred Google+ to Facebook, with less than half saying they preferred it to Twitter. The latter was perhaps an unfair comparison, given that Twitter is a different social beast to Google+.

But what about LinkedIn? We wrote earlier this month that Google+ may actually be a bigger threat to LinkedIn than it is to Facebook or Twitter. For the record, LinkedIn was launched in May 2003, and it didn’t hit the 10m members mark until April 2007. It now has over 100m members.

Interesting statistics. It’s still early doors for Google+ – will it continue on its upwards trajectory, or will it begin to plateau once the hype subsides? Only time will tell.