I've been looking around the entire World Wide Web it feels like regarding GDPR user consent and SharePoint Online. One of the main "corner-stones" of GDPR is to collect and store the consent from the users, they agree on how their data will be processed.
The built-in GDPR support in Office 365 only concerns content of stored documents. The user profiles and user activities (e.g. version history of files) are never mentioned.
In SharePoint (and other Office 365 services such as Teams) there is no standard way to customize a greeting-page at the first login from external users, hence we have no way of collecting consent for how their data will be processed (other than via manual steps).
Am I imagining that the user profiles and user activities should be considered as privacy data and that explicitly collected user consent is necessary from a GDRP perspective?
Edit 2018-09-14 Since SharePoint is often used B2B as part of some collaboration, it could in most cases be considered as a tool for "Contractual fulfillment" as defined by GDPR, hence explicit consent should not be necessary.