Facebook Inc. (Nasdaq: FB) hit its long-awaited milestone of one billion monthly users on its popular social network, CEO and co-founder Mark Zuckerberg announced Thursday.

“This morning, there are more than one billion people using Facebook actively each month,” Zuckerberg wrote on his company’s news page. “If you’re reading this: thank you for giving me and my little team the honor of serving you.”

Assuming that the majority of Facebook users are both real and unique, that means the social network's reach has extended to one out of every seven people on the planet.

News of Facebook’s one-billionth user has been a long time coming, raising some speculation as to why it took until October to achieve the milestone. The massive social media site had already reached 955 million active users in July 2012.

It took Facebook almost four years to acquire its first 100 million users, which it did back in 2008. But since then, Facebook’s ubiquity compared to other social networks (or, indeed, any other websites and internet companies) has continued to snowball.

Despite the continued growth of its user base, Facebook’s financial growth began to seem less likely as its highly-anticipated initial public offering in February resulted in a stock slump for the young company. Reports in August that the company had as many as 83 million fake users shook confidence in just how persuasive the breadth and reach of its user base might be—the one thing that the company was able to leverage for advertising revenue.

Facebook did not mention fake accounts in its statement today, though the company began to purge duplicate or nonexistent users shortly after the problem was first revealed.

When reached for comment on the amount of legitimate accounts in the one billion user pool, Larry Yu, a representative for Facebook’s corporate communications said in an email to IBTimes that the social network estimates “that ‘duplicate’ accounts (an account that a user maintains in addition to his or her principal account) may have represented approximately 4.8 percent of our worldwide MAUs [Monthly Active Users] as of June 30, 2012.”

“We also seek to identify ‘false’ accounts, which we divide into two categories: (1) user-misclassified accounts, where users have created personal profiles for a business, organization, or non-human entity such as a pet (such entities are permitted on Facebook using a Page rather than a personal profile under ourterms of service); and (2) undesirable accounts, which represent user profiles that we determine are intended to be used for purposes that violate our terms of service, such as spamming,” Yu said.

Based on the latest count from June 30, 2012, Facebook calculated that such “user-misclassified accounts” accounted for about 2.4 perecent of worldwide MAUs, while “undesirable accounts” were approximately 1.5 percent.

“As always, our site engineers are constantly monitoring and removing accounts that are found to be false," Yu wrote. “That means we routinely remove these accounts from Facebook. Duplicate accounts that violate our community standards either receive a warning or become disabled, depending on the severity of the violation.”

Since its initial stock market slump, Facebook has responded with a number of attempts to establish more direct revenue streams than simply bargaining with a large user base can afford a public company, saying everything from an improved advertising system or expanded e-commerce solutions could monetize a greater proportion of that same user base.

Facebook also noted that it now has 600 million mobile users, supporting earlier comments by the company about mobile’s expansion compared to the traditional browser-based access to the social media site. Speaking last month at the TechCrunch Disrupt conference, Zuckerberg identified mobile as the main focus for the company in the future. Since then, the company has introduced a new “frictionless” mobile payment system as part of its continued effort to “monetize the mobile web.”

“Chairs, doorbells, airplanes, bridges, games. These are all things that connect us,” Zuckerberg wrote on his personal Facebook page when announcing the news Thursday. “And now Facebook is a part of this tradition of things that connect us too."