Instagram snaps of the delicious meal you're about to eat are such a cliché, they played a starring role in CollegeHumor's hilarious takedown of the Facebook-owned photo-sharing site.

But for restaurateurs, these pics are no joke: People are taking a massive number of photos of food, and Instagram's Photo Map feature instantly shows what's being served at a restaurant. That was the rationale behind OpenTable's $10 million acquisition of Foodspotting this week.

New numbers reported by MomentFeed, a startup that helps brands manage location pages on services like Facebook and Foursquare, show what a huge phenomenon this is.

It's not limited to fancy, upscale restaurants in San Francisco and New York; people are taking huge numbers of photos in chain restaurants like the Cheesecake Factory and PF Chang's.

In an 18-day period studied at the end of 2012, users posted 4,899 photos tagged with a Cheesecake Factory location on Instagram. (MomentFeed only analyzed place-tagged photos, not comments or hashtags.)

Those numbers destroy what's happening on Foodspotting, a service dedicated to this particular art form. Instagram had 40 times the number of photos taken at Chevy's locations versus Foodspotting. At Texas Roadhouse, the ratio was 22 times. And those numbers are typical for most chain restaurants.

Yelp has long offered the ability to upload photos alongside reviews. But a spotcheck of the Cheesecake Factory location in downtown San Francisco, a Yelp stronghold, shows 564 photos posted over the past six years. The pace of posting has picked up recently, boosted by Yelp's mobile app. Our rough estimate shows Instagram users posting two to three times more frequently at Cheesecake Factory locations.

"It's obvious Instagram is the real Foodspotting," MomentFeed CEO Rob Reed told Business Insider. "That's why Foodspotting stalled and were acquired. Vertically focused apps don't make it."

We don't think OpenTable bought Foodspotting for its photo database, of course—it's more about bringing mobile and social talent into the company and setting them loose on OpenTable's larger user base. But even then, Instagram has such a huge head start on food photos, we're not sure how OpenTable will ever catch up.

What's the implication for Facebook? Huge, if it can tie the photos together with Graph Search and location pages.

While Graph Search is currently limited, one thing it can do right now is show all the photos taken at a particular location.

Foodspotting and Yelp both excel at offering detailed information about restaurants. On Foodspotting, users tag photos with specific dishes, while on Yelp, they can write free-form reviews whose text can be mined for insights and relevancy.

But most people are visual, and photos mean more to them. At San Francisco's Cheesecake Factory, there are more than 1,000 photos already—and Instagram promises to funnel far more into the maw of Facebook's voracious data machine.

Facebook can also show friends who have been there. Those links, together with photos, constitute a far more visceral kind of recommendation than OpenTable or Yelp, with their much smaller user bases, can currently offer.

So the combination of photos and friends—Facebook's basic formula—could prompt more local advertisers to take Facebook seriously as an advertising vehicle, if they aren't doing so already.

The only real threat to Facebook comes from Foursquare. At the Cheesecake Factory in San Francisco, Foursquare has 890 user photos. And Instagram currently relies on Foursquare to tie location data to specific businesses; users can simultaneously post Instagram photos to Facebook and Foursquare.

Then again, Facebook could well switch Instagram from Foursquare's places database to its own. And as local-business search gets more and more important, it's hard to imagine Facebook isn't thinking about that.