Website traffic generated by bots has increase by 21% to 61.5% of the total traffic in 2013, according to a report from the security firm Incapsula.
According to the report, website traffic generated by bots accounted for 51% share in 2012.
Bots are the automated software tools and the report reveals a 55% increase in search engines and other good bots that resulted in 31% of the total traffic.
The report said that share of the malicious bots remained constant whereas the Spam Bot activity has decreased to 0.5% in 2013 compared to 2% in 2012.
SEO link building has been considered as a major cause for the increase in automated link spamming.
Duding 2013, the automated link spamming has dropped by 75% due to Google's activities like the Penguin updates.
During the study, which was conducted on a group of 20,000 sites on Incapsula's network for 90 day period, the security firm experienced 1.45 Billion bot visits.
The study claims that the impersonator bot activity has increased by about 8% during the year as a result of the increased activity of such hackers and the growth in targeted cyber-attacks.
The impersonator bot activity is also said to reflect the latest trends in DDoS attacks evolving from volumetric Layer 3-4 attacks to dangerous Layer 7 multi-vector threats.