The article mentions that Evolution provides such a service, but it didn't get heavily used. Quoting from the article

>That system, would require at least two out of three parties in a transaction—the buyer, the seller, and Evolution’s administrators—to sign off on a deal. But due to its complexity, buyers rarely used the feature.

Edit: apparently this does not use bitcoins version of it, but their own that requires them to hold the funds in escrow. Which seems pretty stupid.