Update: Ok, they’ve officially announced the testing of the prototypes directory now. From the company blog:

Facebook Prototypes let us share the experimentation going on inside the walls of Facebook with the rest of the world. You’ll be able to test any of the products and features we launch as Facebook Prototypes and then provide feedback directly to those of us who built them. To access Prototypes, visit the Application Directory and filter by "Prototypes." From there, you can activate or download any of the Prototypes listed.

Original Article: Facebook announced today that not only has it surpassed the 300 million-user mark, but the company is now making money. It was bound to happen sooner or later, and the company said earlier this year that it would happen next year.

Apparently they’re ahead of schedule, because according to Founder Mark Zuckerberg, they became cash flow positive last quarter. "This is important to us because it sets Facebook up to be a strong independent service for the long term," he said.

"Over time, Facebook will continue to be as strong as all of the connections you make," Zuckerberg added. "We’ll continue building new and better things to make connecting with the people you care about as easy and rewarding as possible."

Back to that 300 million number. To put this into perspective, the official 2008 population for the entire United States of America was just over 304 million. That’s a lot of people on one social network.

Now look at some of the things that have been going on with Facebook just in the last month or so: 

- They acquired FriendFeed

- They Launched their real-time search

- They began letting people sell physical goods with their payments platform

- They expanded their staff by 50%

- They’ve been testing a new ads manager and made ads a little more advertiser-friendly

- They’ve been testing a new kind of engagement ad

- They’ve taken steps to increase users’ sharing

- They announced a milestone of 65 million active mobile users

- They’ve hinted at click through rate metrics for Pages

- They have a Google labs-like prototype directory in the works

- They’ve added tagging to the status update

- They’re said to be creeping in on LinkedIn’s territory in the recruiting department

- They launched Facebook Lite

- They open sourced the FriendFeed web server

And that’s just some of the things the company has been up to in the last little while. Suffice it to say, there’s a lot going on with Facebook, and this social network has nearly the same amount of people using it as there are registered citizens in the US…and now they’re making money.

Facebook’s future is looking pretty bright right now. It will be interesting to see what they accomplish in another month’s time. A year’s…