The concept is similar. But Apple only provides this feature on sites that impliment "Sign in with Apple". Firefox Relay allows you to create these relays on the fly, ad-hoc to put into any email field on the web (like sign up for my newsletter fields).
The diaeresis and umlaut are literally exactly the same Unicode character and the symbol or diacritic itself can be called either. The difference is what it does to the vowel — it’s a diaeresis if it indicates a repeated vowel, and an umlaut if it modifies the vowel sound.
That's essentially what Docker containers have done to server-side applications. Every application is isolated from the host in a container and bundled with only the dependencies it needs. The only shared component is the kernel and anything you mount into it from the host.
Possibly part of the reason that other manufacturers did join the programme is that they thought it would help them sell more of their PCs. That was unlikely to be the case with Apple, who had their own marketing and didn't need a sticker to sell a laptop.
In-store Wi-Fi is very common here (UK), and sometimes the only way to get a data connection because mobile signals can't penetrate the building. Only way around it at that point is a to use a VPN over their Wi-Fi if you can.
Instagram does rat out your likes, comments and follows. Check the "Following" tab on the notifications view to see them for those you're following.
It's just down to chance whether the people following you see it, based on how many they're following and how much recent activity there has been with their followings.
