Researchers from Spain have found inconsistencies in counters that YouTube uses to register views reflecting the success of its videos.
"YouTube has a unique system for detecting fraud that is relatively efficient but it has some inconsistencies," said one of the study's authors Rubén Cuevas from Carlos III University of Madrid (UC3M).
The results showed that this data can have economic implications since with some online advertising campaigns that use videos, the portals can charge based on the number of registered views.
The researchers said that companies use "bots" -- computer programmes that replicate the behaviour of an internet user and artificially increase the number of views.
"We discovered a discrepancy in the visit counts on YouTube. Specifically, it seems that there are visits that YouTube detects as fraudulent and, therefore, subtracts from the public views counter (the one that appears near the video), but at the same time Google charges the advertiser for them," Cuevas added.
The method the researchers used to detect fraud allowed them to play the role of different agents: the attacker, the poster of the video and the advertiser who pays to put ads in the videos.
"This allowed us to put our ads into videos that we posted on YouTube and on which we carried out a fraudulent attack. That way, we could have a complete vision of the view count and of how those views were charged to the advertiser," Cuevas noted in the paper published in the scientific archive ArXiV.
With this method, when they sent "bots" to view two videos (exactly 150 times) YouTube's public view counter only identified 25 views as real.
Cuevas said that search engine giant Google has been in contact with the researchers and are showing keen interest in their research.
He said that during same study with Adwords -- Google's main service for advertisers - it charged the researchers for 91 of the views carried out by the "bots".
The findings were presented at the World Wide Web Conference held in Montreal, Canada, recently.