You need to provide anonymous or pseudonymous user identifiers as userToken when tracking Insights events. To identify users consistently, you should provide your own user IDs.
The search-insights library can also generate anonymous user IDs that it stores in a cookie.
This cookie is named _ALGOLIA and identifies users for your Search Analytics and Personalization. You can find more details of this here: Do you store cookies on my website?
If you’d like to store cookies by setting the useCookie:true, you will need to obtain user consent before storing cookies on their device.