Tagging people
Tag a person once in one photo, and PhotoShare offers that same tag on future photos where it recognizes a similar face — you confirm or reject each suggestion, so nothing gets tagged without approval.
Recognition is scoped entirely to your own group; a face tagged in one family's albums has no relationship to a face tagged in a different group, even if it's the same person appearing in both. Once a handful of photos are tagged, open that person's tag to see every photo they appear in across every album in the group, sorted by date.
Tags can be removed at any time, for a single photo or entirely, which also clears any future suggestions tied to that tag. There's no persistent profile beyond what's visible and editable within your own group's albums.