Online shoppers had already spent close to $10 billion ahead of Black Friday, researcher comScore reports. By the end of the holiday shopping season, we'll have spent $37.6 billion online. Retailers hoping to grow those numbers next year had better pay close attention to Facebook.

Fresh data from social media consultant Sociable Labs says that 50% of e-commerce site shoppers are logged into Facebook when walking the e-aisles. What's more, nearly 90% of the top 200 e-tailers tracked by Internet Retailer are integrated with the social network in some way.

The implication? Facebook has become instrumental to pitching shoppers who spend hundreds of billions of dollars annually in the U.S. alone. Growth opportunities don't come much bigger.

Data, data everywhere
How the social network would capitalize on its adjunct role in e-commerce transactions isn't entirely clear at this point. But rich possibilities emerge when you think about what marketers seek.

Advertising is about captivating and connecting with an audience. Know your target and you'll increase the odds of pitching well. Here, by connecting with e-commerce sites where their users are, Facebook is facilitating data that's enormously valuable to ad buyers.

Google (Nasdaq: GOOG) can't be happy about this. The Big G has spent its growth years building an ecosystem for giving people information fast, and in so doing has become like the uncomfortably close friend who knows way too much about you. Yet it's Facebook rather than Google that is getting smarter, faster about the buying habits of millions of e-shoppers.

That's not all. Think what the Dumb Channels must be feeling right now. New York Times (NYSE: NYT), Comcast (Nasdaq: CMCSA), News Corp. (NYSE: NWS), and the rest are working with data from their own sites, yes, but most of what they know is purchased demographic information such as age, gender, and approximate income.

What they lack is intelligence about "liked" products, friends' purchases, follower counts, and similar contextual data. Does it matter? Sure. Precision is always better than ambiguity when it comes to advertising and marketing, and thin-margin e-tailers and retailers want to get their pitches right from the start. Expect the social network to cash in accordingly.

How did you spend your Black Friday? Did you pay cash or pull out the credit card to pay for all those gifts? Next year, you may need nothing more than a smartphone. The Motley Fool recently published a free report that explains how Near Field Communications, or NFC, technology is changing the way we shop. Click here to download now -- the report is 100% free for the asking.