How much your site content is updated is most important. We receive about 300 pieces of new content per month. Each new piece drives a new sitemap into all the search engines, so they crawl us 4-10 times per day. We are always #1 in search priority. FYI, keywords are dead from a Marketing perspective, focus on page tags, content tags, and new content placement and site-mapping, More important is social trend and behavior management.

These are all highly automated today, knowing the behavioral engine logic, and the monetization engine logic and having them in sync is primary mission objective for today's marketing. BTW, most people do not even have a clue on these engines :)