The logical conclusion must be that higher traffic to a website suggests:
- that there is more interest in the site;
- that the site is considered to be relevant;
- that there are more incoming links to the site.
However, to complete the picture, the bounce rate also should be considered. Higher bounce rate implies that visitors are less interested in the site or perhaps that the site is not all that it is made out to be. Therefore if higher traffic is a positive indication, then this needs to be offset by bounce rate (or something similar).
Then of course, more traffic may be due to the successful efforts of the SEO team to optimise the site. If this is the case and traffic leads to improved SERP, then we have a ‘chicken and egg’ situation where the number of visits is related to the ranking which is related to the optimisation which is related to the ranking and so on…
Watch your analytics – measure traffic and bounce rate and try to improve both.
If traffic is important then we also need to consider how the search engines would measure this traffic and this bounce rate. If the web site does not have Google Analytics installed, then can Google get these measures?
Taking all of this into account, I can only conclude that web traffic has little impact on search engine ranking, but is an important measurement and should be monitored by the site owner.