With 1.28 billion registered users, Facebook is the world's largest gathering place. It's where we go to discuss breaking news, announce important life events and gossip about public figures. It's no stretch to say it's the modern-day town square -- only it's frequented by 18 percent of the world's population (and nearly half of all those with access to the Internet).

The only thing missing from this massive virtual meeting place is the village market. In mid-April, the Financial Times reported that Facebook had virtually wrapped up the regulatory process of becoming a “payment and remittance processor.” Then, earlier this month, the social network announced the "Buy" button, showing that social commerce is here to stay.

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For its first 10 years, Facebook focused on the low-hanging fruit of the Internet: advertising. It sold banners that could be hung around the town square, or allowed brands to temporarily use a megaphone to yell over the babel below.

But those were all indirect solutions for what the advertisers really wanted. Brands live on customers, not "Likes." What they wanted was a "Buy" button, and Facebook is finally giving it to them.

The skeptic might see ecommerce as a “me-too” play by Facebook, but the truth is that Facebook was destined to become one of the biggest, if not the biggest, shopping platforms in the world. It teased more peripheral moves into ecommerce in the past, most recently onstage at F8, but the regulatory filings reported months ago show it is finally ready to go all in.

Many of us remember Facebook Credits, the first failed attempt at a virtual currency designed during the Farmville-fueled social gaming boom. Credits may have come and gone in a span of two years, but they were never a serious ecommerce play. Facebook took what it learned from its “virtual goods” experiment and opened up the floodgates to the real thing.

Before long, Facebook will be selling the "Buy" button to big businesses and large retailers, which means that effectively all Facebook pages can be transformed into an ecommerce store.

Social selling. What this means for community managers: the Facebook we see today will look different a year from now.

Thanks to the "Buy" button, transactions will happen instantly, which means social media is now a direct input into the sales funnel. More sophisticated approaches will be developed and needed to support this shift -- the days of racking up "Likes" and "engagements" are over. Sales is king.

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With this change, the role of social-media manager will become something more like a merchant or salesman. They will know when to engage in small talk and when to strategically promote a sale or special offer. They will be data-driven. They will be empowered. And they will have direct impact on revenue.

The "Buy" button will also unlock new data about inventory. To date, social-media managers have only been concerned with community metrics -- number of fans, likes, engagements, shares, etc. -- but in a not-so-distant future they will also be on the hook for bottom-line revenue growth.

If you're a community manager today, change is coming. You won't major in Facebook, you'll major in social commerce.

You will be faced with new, real-time analytics about what is selling and what is not. You will need to play defender of the community and not let pervasive sales teams degrade the relationships you've worked hard to build. You will have to speak sales and social.

In the era of the "Buy" button, everything speeds up, and social sales insights will grow in strategic value.

The future of social shopping. Today, Facebook has a head start with the "Buy" button, but other networks are not far off.

There's too much at stake to sit on the sidelines -- all the major social-networking platforms will eventually offer a unique spin on the "Buy" button.

Brands and retailers need to start thinking about their social selling strategy now, even before the functionality exists. Your competitors will.

Get out your credit cards -- this is the beginning of mainstream social shopping.

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