If Facebook were to charge users $1 for a lifetime membership, Mark Zuckerberg and company would gross $800 million. If the social network charged $1 per month, it would clear a whopping $9.6 billion a year assuming all users were willing to pay up.

A number of Facebook users over the weekend have been updating their statuses to warn of impending charges resulting from changes to the social-networking service. It was a hoax, but it gained traction from an overhaul of the site, including replacing profiles with "Timelines," along with a revamped homepage.

Facebook users have been cutting and pasting this statement or a similar one to their current status:

FACEBOOK JUST RELEASED THEIR PRICE GRID FOR MEMBERSHIP,$9.99 PER MONTH FOR GOLD MEMBER SERVICES,$6.99 PER MONTH FOR SILVER MEMBER SERVICES,$3.99 PER MONTH FOR BRONZE MEMBER SERVICES, FREE IF YOU COPY AND PASTE THIS MESSAGE BEFORE MIDNIGHT TONIGHT. WHEN YOU SIGN ON TOMORROW MORNING YOU WILL BE PROMPTED FOR PAYMENT INFO...IT IS OFFICIAL IT WAS EVEN ON THE NEWS. FACEBOOK WILL START CHARGING DUE TO THE NEW PROFILE CHANGES. IF YOU COPY THIS ON YOUR WALL YOUR ICON WILL TURN BLUE AND FACEBOOK WILL BE FREE FOR YOU. PLEASE PASS THIS MESSAGE ON IF NOT YOUR ACCOUNT WILL BE DELETED IF YOU DO NOT PAY.

But the message was fake. On the opening page of Facebook, it states above the invitation to join: "It's free and always will be."

Given that it is the most popular social network with 800 million users, compared with only 100 million for Twitter and 30 to 40 million for Google+, Facebook doesn't need subscription revenue. Facebook is expected to record advertising revenue in excess of $4 billion this year, according to ZDNet. And the social network, despite having $0 subscription revenues, is worth $75.3 billion, seven times higher than Twitter's $10.7 billion implied value, according to Sharespost, a service tracking private companies. Facebook, the world's largest social network and second most popular Web site (next only to Google), could gross more than $100 billion in an initial public offering next year, according to estimates by analysts.

It's not a bad business plan for charging for online services. WSJ.com offers a mix of free and subscription-only content, and more than one million users have subscribed to the paywall to access exclusive content. Google's Gmail and the seven GB of storage for the e-mail service are free, but Google sells additional storage space to users ($5 per year for 20 GB and $4,000 a year for 16 TB). Zynga provides access to its social networking games for free, but it makes money from the sale of virtual goods and credits. Skype, the voice and video calling service that's being sold for $8.5 billion to Microsoft, doesn't charge for Skype-to-Skype calls and instant messaging but charges $4 a month for unlimited calls to U.S. and Canada.

For Facebook, charging fees might work out. There are a number of users who are willing to pay up to have "verified" accounts. With scams, bullying, theft, and sexual predation on the rise in Facebook and elsewhere online, tracking cyber criminals would be easier if everyone has verified accounts. Scams are thriving on the site because anybody can set up fake accounts.

Aside from verified membership, charging for add-on services might make Facebook less chaotic now that it's one big ecosystem not just for chatting with friends but also for playing games, listening to music, or buying products or services, or making Skype calls. If Facebook works like an Apple App Store or a Sony PlayStation network, you won't need to input credit card details every time you buy credits for your poker games, purchase music in a forthcoming iTunes-like music service or watch videos in a Netflix-like service Facebook will likely implement soon. With many entities selling goods and services on Facebook, it would be safer if Facebook implements something like a Paypal-like currency trading system.

Hence, Facebook charging for services in the future might no longer be a hoax. It's not a question of "if", but "when."