Dig a little deeper, and you may also have noticed that this increase in referrals is coming from a set of strange domain names such as semalt.com or 72.semalt.com.
Semalt is ostensibly a web analytics company offering a number of webmaster and search tools. However, unlike more well-known search companies, such as Google and Bing, Semalt’s site crawlers act in such a way as to register in Google Analytics as a normal referral visit. In other words Google Analytics treats the visits like those of a human user, rather than a robot crawler.
Every time Semalt sends a crawler to your website, it will register as a regular site visitor which has been referred to your site from a Semalt domain or subdomain. These Semalt visits are characterised as being short in duration (0 seconds) with a high, 100% bounce rate.
Unfortunately, if a website gets a sudden increase in Semalt visits, it will skew the site’s overall statistics. This skewing effect is particularly notable in websites with relatively low daily visitor numbers (below 20) as the distortion is so much greater.
Average visit durations tumble, average visit depth (number of pages per visit) decreases and average bounce rates go up. Taken as a whole, Google Analytics will show a website’s performance as having taken a marked hit.
Indeed it is possible that, over time, the statistical decrease in the website’s performance could have a detrimental impact on its search engine page ranking.
Semalt have said that concerned webmasters can contact them directly and they will stop crawling the reported website(s). However due to the company’s spammy crawling practices, initiating contact with them is not recommended.
Semalt traffic can instead be blocked from crawling a website, by updating the site’s htaccess file. For more information please get in touch.