[biot]

Instagram does this. They let anybody sign up for an account using any email address, and the account is immediately live. While they send a verification email, you don't have to click on it to still use the account. And most likely if you hadn't signed up for the service you'd think it's a phishing attempt and ignore it anyways.

I found this out the hard way when someone else had created an account under my email address and because some of my friends had uploaded their address book, my friends were following this stranger, perhaps thinking it was me. When I eventually did choose to sign up, I had to jump through a bunch of hoops just to be able to use my own email address.