Cross device tracking with user ID (authenticated sites/apps)
I´ve many questions in regard of cross-device tracking:
1. We have many websites and a couple of apps (authenticated ones) that we would like to track the users. For instance, one of our products has an app and web version and some customers use both. But on a monthly basis, this user is the same for us, regardless of the platform it used, so we would like it to be unique (active user). What would be the best way to track this user? Would it be using our authentication ID (userID) since this ID is unique for each user?
We do have a global report suite that we would also like to know about this user journey among all our authenticated products.
What are the options to accomplish that?
2. setting up a user ID.
for our websites we already have that, we have an userID eVar that is the same in all our report suites, including the global one, and getting the userID from a data layer. However, we are struggling to do the same for our app.
In the app, I do understand the general idea that context data should be added in the app, and then a processing rule created to overwrite this value with the eVar.
But going deeper (I'm no dev here), how will the context data pass the user ID information? what should be inserted in the code? we did a test previously that we managed to send this ID with track state (i think it was it), but first, we need to see all the IDs in the eVar and cross it with the other sites and guarantee we are not sending extras pageviews.
The idea would be like the web, to know all the pages that each ID visited.
3. Considering our app is not native, is there a way for this context data to be created via launch instead of inserted in the SDK? but again, if via launch, how will we point out how to get the unique user ID?
4. How would the processing rule look like?
Sorry that I'm asking step by step but it's really difficult to find documentation and information about mobile apps that are detailed and/or show step by step of processes, even more now with the mobile services UI end of service.
Thank you so much in advance!