comScore, the digital world experts, has today released the results of a study on Facebook.com.

The results show that the site grew to 26.6 million unique visitors in the US in May 2007, marking an 89% increase in comparison to the same month last year.

The dramatic growth is due to Facebook.com’s decision in September 2006 to open up the site to the general public, a move away from the strict schools- and certain businesses-only policy previous to this.

At the time the decision garnered criticism and protests from Facebook users who wanted the site to remain closed, these protestations were disregarded and largely attributed to college students not wanting their parents to be able to spy on them digitally.

comScore reports that the number of pages viewed on Facebook.com in May 2007 increased to a mind-boggling 15.8 billion, up 143% versus May 2006.

Despite its start as a tool for college campuses, Facebook’s open registration has helped attract new visitors from outside the 18-24-year-old group.

The largest increase was seen among 25-34-year-olds (up 181%), while 12-17-year-olds grew 149% and those age 35 and older grew 98%.

A comScore spokes-spert said: "Since the decision to open registration to everyone, the site has seen visitors from all age groups flood the site".

"As the overall visitation to Facebook continues to grow, the demographic composition of the site will likely more closely resemble that of the total internet audience."