After several years of declining search traffic, Condé Nast CEO @rogerlynch has directed all the company's brands to operate as if search traffic to their properties will be zero. He says the era of turning search and social media traffic into profitable businesses is gone. And that if you run a media business that doesn't have an authoritative brand, a very strong niche, or a direct audience, you're going to be fighting hostile algo changes all the way down. He describes a recent board…