Search engine optimization has changed dramatically during the course of the past fifteen years.
Believe it or not, there was once a time when the sole measure of SEO success was where a site ranked on the popular search engines of the day. Websites were pleased that they ranked for a particular keyword in a particular position. Those days are gone however.
Keyword rankings are unstable, personalization makes reporting inconsistent at best, and it's increasingly difficult to understand what actual strategies are paying dividends in the form of traffic - particularly as the influence of social increases in importance.
So how do you (and others) measure SEO performance/success for your Websites and digital properties today? While the approach your enterprise will take depends on a variety of factors, here are the most common:
The savviest enterprises (and their SEO's) know that the one ideal measurement of success when it comes to search engine optimization is conversions - sales, signups, however they are defined for a specific digital property. Search engine optimization agencies, at least the pure-play vendors (i.e. not integrated digital marketing agencies), tend to shy away from using conversions as the sole proof of performance because there are so many other variables that come into play - namely design, price, checkout, etc - that may interfere. That's really why there are so few performance-based SEO agencies in the market - because they need more control over the total experience, and many enterprises are simply unwilling to let that control go.
Since most SEO agencies are unwilling (or uninterested) in convincing their clients to adopt a conversion-centric SEO campaign, most opt to measure their SEO performance by the number of unique visitors that arrive on their website properties. It's a terrific measurement, of course, but it can't tell as deep a story as measuring by conversions. There's another problem too, a big one. While the "keyword not provided" issue is a rather significant issue for websites interested in knowing why users are arriving at their site, some SEO's love it - particularly if they are using longer tail search phrases to drive traffic which may or may not ultimately provide much in the way of conversions or sales. In essence, you can get all the traffic in the world, but if users aren't actually acting upon your unique selling proposition, efforts are for naught. Of course, that doesn't much matter if the only performance metric is unique visitors.
Conversions and unique visitor traffic are clearly good indicators of SEO performance by themselves, but despite all the complexities of the modern search engine experience (which is both highly personalized and dynamic) the actual rank of a site still remains a pretty good measurement. You may be thinking, "No it's not - everyone's search results are different," and that's true but there is a way to get a good idea about where a site is ranking on average for a particular keyword/keyphrase. For example, it's quite easy to set up a campaign on Amazon's Mechanical Turk and pay a few cents on average to get one of their knowledge workers to fire up whatever search engine you are measuring results for and let them, in aggregate, determine the average placement which can in turn be used in reports to clients or yourself.
Website Magazine is running a poll today on its Facebook page about common ways to measure the success of search engine optimization efforts (those approaches listed above). Cast your vote now and we'll be sure to share the results.