Posted by Shuman Ghosemajumder,
Business Product Manager for Trust & Safety
We recently began a series of
posts on how we harness the power of data.
href="http://googleblog.blogspot.com/2008/03/why-data-matters.html"
>Earlier we told you
style="font-style: italic;">how data has been critical to the
advancement of search technology.
href="http://googleblog.blogspot.com/2008/03/using-log-data-to-help-keep-you-safe.html"
>Then we shared how we use log data to help
make Google products safer for users. This post is the newest in
the series. -Ed.
Protecting our advertisers against click fraud is a lot like
solving a crime: the more clues we have, the better we can
determine
href="http://adwords.blogspot.com/2007/02/invalid-clicks-googles-overall-numbers.html"
id="v4:f" >which clicks to
mark as invalid, so advertisers are not charged for them.
As we've mentioned before, our
href="http://adwords.blogspot.com/2007/02/meet-click-quality-team.html"
id="v3:6" >Ad Traffic Quality team
built, and is constantly adding to, our
href="http://adwords.blogspot.com/2007/02/invalid-clicks-googles-overall-numbers.html"
id="uta7" >three-stage system for
detecting invalid clicks. The three stages are: (1) proactive
real-time filters, (2) proactive offline analysis, and (3) reactive
investigations.
So how do we use logs information for click fraud detection? Our
logs are where we get the clues for the detective work. Logs
provide us with the repository of data which are used to detect
patterns, anomalous behavior, and other signals indicative of click
fraud.
Millions of users click on AdWords ads every day. Every single one
of those clicks — and the even more numerous impressions
associated with them — is analyzed by our filters (stage 1), which
operate in real-time. This stage certainly utilizes our logs data,
but it is stages 2 and 3 which rely even more heavily on deeper
analysis of the data in our logs. For example, in stage 2, our team
pores over the millions of impressions and clicks — as well as
conversions — over a longer time period. In combing through all
this information, our team is looking for unusual behavior in
hundreds of different data points.
href="https://adwords.google.com/support/bin/answer.py?answer=6322"
id="r4u0" >
href="https://adwords.google.com/support/bin/answer.py?answer=6322"
id="r4u0" >IP addresses of computers
clicking on ads are very useful data points. A simple use of IP
addresses is determining the source location for traffic. That is,
for a given publisher or advertiser, where are their clicks coming
from? Are they all coming from one country or city? Is that normal
for an ad of this type? Although we don't use this information
to identify individuals, we look at these in aggregate and study
patterns. This information is imperfect, but by analyzing a large
volume of this data it is very helpful in helping to prevent fraud.
For example, examining an IP address usually tells us which ISP
that person is using. It is easy for people on most home Internet
connections to get a new IP address by simply rebooting their DSL
or cable modem. However, that new IP address will still be
registered to their ISP, so additional ad clicks from that machine
will still have something in common. Seeing an abnormally high
number of clicks on a single publisher from the same ISP isn't
necessarily proof of fraud, but it does look suspicious and raises
a flag for us to investigate. Other information contained in our
logs, such as the browser type and operating system of machines
associated with ad clicks, are analyzed in similar ways.
These data points are just a few examples of hundreds of different
factors we take into account in click fraud detection. Without this
information, and enough of it to identify fraud attempted over a
longer time period, it would be extremely difficult to detect
invalid clicks with a high degree of confidence, and proactively
create filters that help optimize advertiser ROI. Of course, we
don't need this information forever; last year we started
href="http://googleblog.blogspot.com/2007/03/taking-steps-to-further-improve-our.html"
id="yu6a" >anonymizing server
logs after 18 months. As always, our goal is to balance the
utility of this information (as we try to improve Google’s services
for you) with the best privacy practices for our users.
If you want to learn more about how we collect information to
better detect click fraud, visit our
href="http://www.google.com/adwords/adtrafficquality/" id="bwg:"
>Ad Traffic Quality
Resource Center
Tags: , Business, Ghosemajumder, manager, Posted, product, Shuman, Trust
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