What happens if I switch a 'friend' to an 'aquaintance'?

[Mysterious World]

What kind of updates do I get?
Secondary question, what do I see if I switch to 'only important updates'? Presumably there is some overlap between these categories...?
Thanks

[Theo Smith]

With a friend you get most updates, like things that they've liked, people they've added as friends, etc.
With an aquaintance, you don't get as many updates. Only things like new profile/cover pictures, status updates, etc.
If you set it to only important updates you practically get the same as aquaintances, just a tiny bit less. For example, relationship updates.

So basically, if someone posts way too much, or likes too many things, add them as an aquaintance, and if they still pop up on your news feed, set it to only important updates.
Failing that, just block them.