The questions posed is: Which is more important, Alexa or Google. In my view, for the average web person, Google is far more important to determining your web traffic, while Alexa is simply a reflection of your success on Google and on search ranking in general. High rankings on Google lead to successful stats on Alexa, which ranks websites based upon the traffic they receive.

With regard to actual traffic, Google bases the traffic based upon backlinks. While Alexa determines traffic through a toolbar. The pagerank of Google may not give an accurate determination of traffic for smaller websites. On the other hand, Alexa only measures the top domain and not subsequent pages separately.

This Alexa ranking is from a random sample, because it is derived from the readings off the Alexa toolbar that is downloaded on what one hopes is a random accurate sample of net users and surfers. Of course, those inclined to download the toolbar in the first place may have biases regarding the kind of websites that they search out. But there are so many of them that they do give a fairly accurate picture of web activity in general.

Of course, for the web promoters with the bucks, buying Adwords becomes the advertisement of choice, and that affects Alexa rankings. Still, the foundation of this Alexa jump in rankings, while bypassing pagerank, still involves Google. Unless you advertise with Yahoo and other search engines and bypass Google, you are going to be factoring Google in as a crucial reason why your Alexa stats are improving.

So then, there may be some websites who use other forms of advertising other than Google, who may find Alexa to be more important, but the vast majority of websites will find Google more important because of pagerank or because of adword advertising.

If you are hosting advertising on your website, Google pagerank and Alexa rankings both can be important measures of your website popularity, allowing for a good return on advertising.

Alexa does have one really good feature, a way of comparing your website to others, ie your competition! Ultimately your Alexa ranking could prove to be more important than Google PR simply because the contest is a numbers game. PR does not always reflect high traffic, but Alexa rankings reflect total traffic.