Facebook wasn't the only one making big changes to its social network last week, Google added new features, mostly to Hangouts, and opened the site to all. We figured the latest additions and accessibility might have a draw, which had yet to take off. And it looks like it has. Traffic is up, reports web traffic analytic company Experian Hitwise. "Opening access created a massive spike in market share of visits for the site, with a 1269% growth from the week ending September 17th to the week of September 24th. The site also received nearly 15 million total US visits last week." That's up from the usual 1 million. Before you deactive your Facebook account, let's break down the numbers. Facebook's still insanely dominant.

Beyond the traffic bump, the site also hooked more new members, according to Paul Allen, founder of Ancestry.com who using an algorithm based on U.S. Census data correctly predicted the 10 million user mark.

On September 9, our model showed 28.7 million users. This morning, our model shows 37.8 million users, with most of the growth coming in the last 2 days. By adding a fudge factor (see below) to account for private user profiles and for non-Roman surnames (both of which are totally overlooked by our surname counting model), my current estimate is 43.4 million users G+." But signing up Let's break down the numbers.

That's a 30 percent increase in just two days.

It seems fairly straighforward that Google+'s membership and traffic numbers would go up once the company opened the service to the world. As we've noted before, this growth isn't exactly organic. At first invites went out to select techies, then invites became ubiquitous and now it's an open house party. With months of buzz of course people want to check it out. Not to mention: Google makes it very easy to sign up, especially if you already have a Gmail account. 

The real question is: Will the traffic last? A month after its explosive launch, interest in the site slowed, as we noted

Total Google+ visits fell 3 percent in the fourth week since its launch; the week before that Google+ visits had risen 283 percent. Fewer new users is bad news for a site that hopes to beat Facebook's 750 million mark. But perhaps even more worrying, average time spent on the site declined from five minutes to 15 seconds, meaning the millions who have accounts don't really use them.

New users might experience the same fatigue. And the demographics of the users aren't too promising either. The site is still failing to draw regular Internet people. Early adopters abound, found Experian: 

In comparison to the online population, Google + continued to over-index for and win a high share of its visits from Mosaic USA 2011 Types which contain 'Influencers', 'Early Adopters' and the internet-savvy, like 'Bohemian Groove', 'Gotham Blend' and 'Progressive Potpourri' ; this indicates that 'Early Adopters' still account for a large share of Google+’s traffic. "

The growth may look huge, but when compared to Facebook, the site still looks pretty measly. "In just one week, Google+ went from ranking as 54th most visited site in our Social Networking and Forums category to 8th place," Experian found. But taking a closer look, Facebook still dominated with 64.85 of all that traffic, whereas Google+'s 0.55 percent is sandwiched between MySpace and myYearbook.com.  But if Google+ can keep up this type of growth, though, things might get interesting.