we do not share your data with anyone and there are many ways to control the visibility and storage life of your data here.
but the internet is a public space and you should always assume your data could be compromised.
be smart with your password, use tor or a vpn, and use pgp for sensitive communications.
You just did pretty well with your subject image ;). Other options are adding it to a post (add media) or to keep it private you could make a password protected item and give the vendor the password.→