The single most effective thing you can do with malicious users like this is to let them think that they have won. In the ideal case, you can detect simple click frauds and maintain a per user play adjustment so that they see the fraudulent stats and everybody else sees the corrected stats. If you can, this should even extend to your leader board pages. Once you have this, the fraudsters will generally not increase the sophistication of their attacks and you have a fairly simple situation.
You also will have a bit of an advantage if you pick a metric that indicates fairly serious engagement. With videos, for instance, I have used plays > 30 seconds as the metric and this was handled by a beacon on the page while the 30 second delay measurement was on the server side. This requires a browser to be live and in focus for 30 seconds in order to get a play event which substantially increases the cost of committing the click fraud on the fraudsters side. With the recommendation analysis itself, the key is to flatten all frequency metrics per user. With unsophisticated click fraud, the abuse will center on creating high play frequencies for a few users which will then be counted as a very small input signal since so few users are doing it and their high play rates won't matter. Also, the major effect if any will be to simply give the fraudsters recommendations for their own items which will make them happy and won't matter to anyone else. On Tue, Aug 28, 2012 at 6:29 PM, Zia mel <[email protected]> wrote: > Hi , > > Is there any way to check for malicious users in mahout so I can > remove them from the recommendations or reduce their effect ? > Malicious users are the ones that want to play with the ratings and > increase or downgrade it. > > Thanks, >
