In this video interview, web analytics expert John Marshall explains why old measures of organic SEO success are flawed, and what new measures give you an accurate picture.
We used to use a program like Web Position Gold, says Marshall, to do a search and scrape the results to show us the relative ranking for a keyword. Google's PageRank would show the relative linking to a webpage. But these days, localization and personalization in search results now make ranking reports innacurate.
Localization. Google is much more diligent to target search results (and paid ads) based on location, so you would find different results for a search done in Sacramento compared to one conducted in San Francisco.
Personalization. Google also personalizes your search results based on previous searches. Google cookies you, so personalization works whether or not you are logged in to your Google account.
Universal search has changed eye-tracking patterns, so a #1 ranking may not have the value it used to. But this is pretty obvious to people, while localization and personalization are more subtle.
There are ways, however, to do a more accurate measure of SEO effectiveness. Some people use traffic as a measure. But if overall searches that month increase greatly, it could mask a drop in your own SEO effectiveness.
Share of Search (sometimes referred to as Share of Voice) is a more accurate measure. This is determined by dividing traffic to your site (obtained from your analytics program) by the total searches (obtained from Google Insights for Search). However, Google Insights for Search gives you an index, not an absolute number. So you'll need to create an index in Google Analytics, comparing top search terms to total traffic to your site -- then compare your index with Google Insights for Search.
Marshall likes Compete.com to determine relative SEO effectiveness. The free version allows you to compare your site with two competitors. This works because organic search results are a zero sum game. When you win your competitor loses, and vice versa.
John Marshall is the co-founder of MarketMotive.com, which sells training courses that you can take online that will teach you all the latest techniques in Internet marketing. Courses can be taken from the convenience of your office, with a structure course, tests, and a certificate of completion. This interview was recorded at the Search Engine Strategies Conference in San Francisco, Auigust, 2010.