Maybe blockchains immutability is going to actually make people think twice before putting something online.

"Web2" makes us think that we can delete whatever we post, or what we send is not going to be stored. And we believe it because it is technically possible, even though we don't have any way to double check.

If a service claims that you can delete/hide whatever data you uploaded on the blockchain, you'd be able to verify it and not only trust them. And if you are told that using this service, there is no way to delete it, and that anybody can see it, you might avoid doing something that you'd have done with web2 and regretted later.