"Some Web services invite you to give them personal information. I usually don't use them because I don't want them to have information about me. Some of them invite you to hand over a lot of data, saying that they will keep it for you. That is something you can trust if you can encrypt the data so they cannot possibly tell what any of it means. They could provide a useful backup service this way. Some services do computations for you, which you should never do because you should have complete control over your own computing. And other Web services may not do those things, but many of them do surveillance, which is collecting information about you, other than by just asking you for it. ... I generally do browsing from other people's computers or in places where there are shared computers so that they are not associated with me. I mostly do computing within my own computer."