There may be a node. But even so, it is a myth that the social networks know everything from other people's shared information.
WhatsApp does not know which people/entities I have in my contacts list.
That cannot be deduced from other ordinary people's lists.
It is a two-sided issue. On the one side: We should understand that we can't completely hide our personal information because other people share it without our consent, and that we should all be more careful what we share because it can harm other people, and is without their consent.
But on the other side: There is still value in limiting what we share about ourselves and others, because what other people share is limited and does not produce as complete a picture as when we add more to it ourselves.
So, WhatsApp knows about specific contacts other people have entered which include me, but it doesn't know what's on my full list. There are many things which can be estimated from my contacts list which I don't want to share and can't be deduced from other people's contact lists:
- Which banks I bank with.
- Which credit cards I have.
- Which recruiters I've been talking with.
- Which prospective companies I've talked with about getting a job.
- Which clients I'm doing business with or have done.
- Which taxi firms I use.
- Which restaurants I know well enough to have in my list.
- Which lenders I'm borrowing from.
- Which debt collectors I'm talking or not talking with.
- Which people I have a secret affair with, who are smart enough not to share their contacts list.
- Which journalists I'm in touch with, who are smart enough not to share their contacts list.
- Who I'm organising protests against the state with, who are smart enough not to share their contacts list.
- Who I know well enough to have not just their number but also their email address and other contacts, home address, notes etc.
- Which other communication applications I'm using if those store contacts in the list.
As well as the number of each of the above, to suggest which aspects of my life to target for advertising, policing, or general intimidation and election manipulation.
