Why does that require having a profile on you in particular? They could be saving all the data from everyone else (e.g. their contacts, their search queries, et

Why does that require having a profile on you in particular? They could be saving all the data from everyone else (e.g. their contacts, their search queries, etc.) and dynamically assembling it when you make an account to make you recommendations. They don't have to be doing anything related to you in particular.