The search giant argues that it will be able to tailor advertising more effectively to users’ interests.
The move has been met with criticism from organisations including French regulator CNIL, which has flagged the privacy changes as potentially unlawful.
Google has defended its move and said users can opt out of the service by changing their settings within Google’s dashboard.
Marketing Week looks at the implications for marketers.
What does it mean for advertisers?
Essentially it means advertisers can better target online users. Google will combine information about each of its logged-in users as they use different Google products, such as Google Calendar, Gmail and Google+, to target them with tailored advertising.
What does this mean in practice?
By combining its data, Google will have much more precise data on its users. So for example if a user is searching Google for a holiday in Ibiza for June, they could be served advertisements from travel agents with an offer for Ibiza while they’re watching videos on YouTube.
How does it benefit advertisers?
Using the information Google collects by combining the different data across its various properties, the search giant will be able to create profiles on its users -basically a fuller picture of who their users are.
Advertisers will hope that by serving more relevant advertising, consumers will be more inclined to click through to their ad and in turn, increase sales.
What are the issues surrounding the move?
The search giant has come under attack by the French regulator, CNIL, for potentially violating the European Union’s data protection laws.
CNIL asked Google to delay its policy change, but the search giant has gone ahead with the changes.
Users who feel uncomfortable with the changes could stop using Google or clear their web history, leaving Google and advertisers a bit more in the dark on the creating a picture of each user. However, this is likely to only amount to a small number of its users.
Where next for Google and advertisers?
As Google moots bringing its TV service to the UK, the potential to advertise to consumers based on their viewing habits could take targeted advertising to a whole new level.