POV: Google’s Global Site Tag

Google’s new Global site tag is a simplified web tagging library that works across all of Google’s site and conversion measurement products, giving better measurement for all Google tracked activity (Analytics, AdWords, Search, DCM & DBM [Display]). This approach also helps to negate some of the issues caused by the recent change to Safari 3rd party cookie setting and deletion (Intelligent Tracking Prevention or ITP) due to the recommendation that the new pixel is placed across all pages.


Floodlights and AdWords conversion pixels have been traditionally confined to events on a website that have some value/insight or are a KPI for a marketing campaign (sale, email sign up, product configurator). This gives only partial visibility into the user journey and reliance on the setting of 3rd party cookies means that ITP will create gaps in the user journey for many conversion funnels, which is a real issue for advertisers.

Google says that its new global pixels should be allowed to set first party cookies across all pages on a client’s site. This is technologically identical to using Google Analytics on-site, even if only a single channel is being used (i.e. Search or AdWords, or just using DCM as a stand-alone ad server). Given Google’s ownership of inventory (GDN, YouTube and of course Search) this raises interesting questions on how the enhanced site data could be used to help Google price its inventory in line with cross channel user behavior - even if only one or two Google channels were used in the conversion journey.

The new cookie also requires JavaScript tags to be deployed, which goes against the wishes of many large advertisers that insist on image tags to control data leakage and enhance site security.

It will be interesting to see how the roll out of GDPR impacts this new approach.

Also, how will Google’s conversion reporting be impacted if either the site owner or end user don’t allow permissions to be set? Google has stated that it will extrapolate the data but as with all Google data pass-through, that calculation is done behind the scenes, so methodology and weighting assigned will remain opaque to the agency and client. The alternative is to have IPT remove tracking cookies, which will give a disjointed view of user journeys for Safari users (often a very desirable targeted demographic), something that is far from ideal in a data-driven world.


Global site tag offers more accurate conversion tracking and faster/easier integration with other Google products, so for anyone utilizing the full or partial Google Tech stack it would be an essential upgrade to their tracking. However, some advertisers may not like giving Google the opportunity to set first party cookies on their website, which is a core component of the update. Restricting this feature will lead to less accurate measurement.

There has been no word from Google on any plans to decommission the old tags yet, but given the push for a more easily integrated single tech stack, this must be a long term goal. How this affects clients unwilling to allow Google to set 1st party cookies will be interesting to see develop.   

Further reading:

Google Support Page / Doubleclick Blog Post