"Use keywords in your URLs and file names, such as yourdomain.com/red-widgets.html. Don't overdo it, though. A file with 3+ hyphens tends to look spammy and users may be hesitant to click on it. Related bonus tip: Use hyphens in URLs and file names, not underscores. Hyphens are treated as a "space," while underscores are not. - searchengineland.com"