Two-year-old Just A Pinch Recipe Club, the brainchild of serial media entrepreneur Dan Hammond, hit a big milestone recently when a Pennsylvania woman posted the 100,000th recipe to the website. That's 30,000 more than the site had last December.

Hammond credits the rapid content growth in large part to the network’s “stickiness.” Users call the site the “Facebook of recipes” and spend upwards of 17 minutes per session with up to 50 percent visiting the site one to three times or more per day. That ranges from 5 to 8.5 hours on average per month, which rivals or even exceeds some of the largest horizontal social networks including Facebook, Pinterest and others.