With Penguin, Google was addressing the “off-page” optimization of sites. Primarily the back links that point to your site from other websites.
In its simplest explanation, you MUST pay attention to this or have someone on your team that is. If it’s done incorrectly, you can (and many have been) get kicked out of Google search results altogether.
And there you have it – either you want organic traffic… or you don’t. Either you want to experience the thrill of marketplace domination, or you don’t. You’re either in our out.
If you say “I’m in” but simply need help to compete, that’s what I (leader of one of the nation’s best SEO firms) do for my clients, so contact me here and let’s talk.