Google to build profiles of Gmail users for advertisers
Google is to begin building up profiles of Gmail users based on the contents of their emails, in order to better target them with advertising.
A new system will read emails to learn about what users are interested in and what their priorities are, based on "signals" such as what they receive the most email about, which emails they read and reply to, and the identity of their most regular contacts.
Google's plan will make significantly more use of users' private data to target advertising on Gmail: until now, it has served up sponsored links based on the contents of individual emails, rather than a detailed, stored profile of the recipient.
For example, Google said in its help page about the changes, "if you’ve recently received a lot of messages about photography or cameras, a deal from a local camera store might be interesting".
"On the other hand if you’ve reported these messages as spam, you probably don’t want to see that deal," it said.
Google explained that its new Gmail advertising will take a similar approach to "Priority Inbox", a feature introduced last year which automatically judges whether emails are important based on how comparable ones have been treated in the past.
It also said that as a result of the new technology, it expects present fewer advertisments to Gmail users and that no emails or personally identifiable data would be shared with advertisers.
Gmail's move to "interest-based advertising", as Google calls it, is in line with the trend among web advertisers towards what is usually known as behavioural targeting.
In 2009, Google itself began introducing behavioural targeting to its AdWords advertising system, which is by far its biggest source of income.
Such technology has prompted fierce debate between the web advertising industry and privacy campaigners, who argue that users do not have adequate control over how they are profiled or how the data is used, and have called for tighter regulations.
Google said Gmail users who do not want their emails to be profiled for behavioural targeting will be able to opt out of the system when it is enabled on their account.
"Only a few users will notice the change to begin with, but as we improve it we’ll roll it out more widely," it said.