[maratc]

This could be a little more intelligent.

E.g. a coffeeshop has a constant stream of accounts on its IP that appear only once or twice. So it might be considered "a public place". So no association is done over accounts arriving from that IP. Your home, OTOH, might have only two accounts on its IP for years, so the association here is stronger.

A cookie shared between two accounts is even a stronger indication, as a person used the same browser to log in with both.

The system might not be created "to prioritize Maps suggestions" only and has multiple benefits in other places. Most obvious of these is to prevent people banned from the service to come back with a different account.

(I don't work at G and never did, but worked at another place where we linked accounts.)

[Thorrez]

Sure it could be more intelligent, but there would always be false positives. For example a Google employee's spouse could likely get correlated. False positives sounds like a bad idea for a system that tries to match personal and work accounts. Also in my case it would be harder possibly because I have a ton of personal Google accounts.

>A cookie shared between two accounts is even a stronger indication, as a person used the same browser to log in with both.

I never use the same browser for my work and personal accounts. But in theory that could run into the spousal problem as well for some people.

[maratc]

There is a ton of other information. E.g. for the “security” you are asked to provide a backup email address for your Google account. Also, for the same reason, everyone is now required to provide a cellphone number. If you used one of your Google accounts as a backup for another, or used the same recovery phone number for both, these two accounts can be linked to a same person. This comes in addition to other information about possible links, like geolocation or other trove of data they might have. If you added several accounts to check emails, your phone checks all of them every couple of minutes, from the same IP at the same time, whether you’re at home or not.

In short, the amount of data you are passing to Google, willingly or not, allows them to link these to a single person — you — with an extremely high certainty.