Google+ has hit 25 million users already and is the fastest growing website to reach that audience size, according to recent findings by comScore on Tuesday.

Just launched in June 28, Google's new social network had hit 25 million unique visitors as of July 24 says Andrew Lipsman, vice-president of industry analysis at comScore. The social networking site is growing at a rate of roughly one million visitors a day, he said in a presentation.

Compared to Facebook which took about three years to reach 25 million visitors or Twitter which took over 30 months, Google+ is the faster growing site at roughly the same period.

The data did show that while Google+ is clearly having a better start than the other social networks, Facebook, Twitter and Myspace have bigger audiences than Google+. It also doesn't mean that such a strong start will lead to long-term success. MySpace grew to 25 million visitors in less than two years but has lost ground to Facebook and Twitter since then.

Research also shows that people spent about 50% more time on the network in the week ending July 24 than the previous week, which debunks a recent report from Experian Hitwise that said Google+ fell 3% for the week ending July 24.

Google+ rapid growth is due to Gmail penetration, according to the report. Gmail has powered Google+ popularity. Lipsman estimates that roughly 20% market penetration is needed to firmly establish social networks.

In other data the U.S. had the most unique visitors with 6 million followed by India with more than 3.6 million. Canada and the UK had around 1 million unique visitors. Germany had over 920,000 and Brazil just over 780,000. France and Taiwan each had around 500,000.