Does the collective wisdom of the Web really say that J.C. Penney has the most essential site when it comes to dresses? And bedding? And area rugs? And dozens of other words and phrases? The New York Times asked an expert in online search, Doug Pierce of Blue Fountain Media in New York, to study this question, as well as Penney’s astoundingly strong search-term performance in recent months. What he found suggests that the digital age’s most mundane act, the Google search, often represents layer upon layer of intrigue. And the intrigue starts in the sprawling, subterranean world of “black hat” optimization, the dark art of raising the profile of a Web site with methods that Google considers tantamount to cheating.