With users' behaviors and Google's algorithms rapidly and constantly changing, measuring SEO success by your ranking position for your favorite keywords means falling behind the curve. Here are the most meaningful metrics for SEO for 2013.

1. Focus on Your Keyword Portfolio, Not Rankings

Search engine users are getting smarter and more specific. Today, over 70 percent of searches online contain three or more words in the search query. Furthermore, Google reported that over 20 percent of search queries are completely new queries that had never been searched before! The long tail is where the growth is happening, and your strategy needs to be built around this growth.

Focusing on "fat head" keywords is an unbalanced strategy with diminishing returns. Marketers need to focus on increasing the number of keywords sending search traffic rather than improving a specific keyword position. This is known as your keyword portfolio.

2. Create Problem-Solving Content

Creating great content isn't rocket science. If you have trouble coming up with ideas, or you think your industry is too boring, focus instead on solving a customer's problem. This can be done easily by utilizing your organization's intellectual property to create how-to guides, white papers, or research studies. If you're in business, then you're solving problems! Combine people, processes, and software to scale content marketing.

3. Publish Content on Quality Sources

Last year's Penguin update eliminated the value of content published on untrusted websites. This includes low-quality websites, content farms and many "free" PR websites. Showing up in Google search is a lot like getting a job--it's your references that make the difference. Concentrate on earning references from high quality and trusted industry websites. Industry organizations and online communities are where you should be publishing content on a regular basis.

4. Distribute and Promote Content through Social Media

Social media is an extremely efficient channel for distributing and promoting your content. This includes content that you publish on your website, as well as content that you publish on highly trusted third-party websites. Social media channels enable you to reach millions instantly, as well as stay on the radar of search engine algorithms for topics related to your content. Google and Bing have both admitted to using social signals in their ranking algorithms, so social media engagement is a must-do for digital marketers.

Never before have SEO and inbound marketing had more potential for digital marketers. When executed effectively, these strategies will drive leads, attract customers, and grow your brand's community.