I recently deleted my Linkedin account. But their junk emails continue to dirty my email even now. Next in the line is Skype, and then probably Facebook.
Thankfully, I never shared my genuine data with Facebook or opened an a/c on Instagram or Whatsapp ever so I'm good at a certain level when it comes to Facebook.
In my opinion Twitter is the only option that is sane at the moment.
I tried many times to uncheck all the checkboxes to convince LinkedIn not to send me email, but they ignore them or create new ones, so now I just mark them as spam.
username+whatever@gmail.com is delivered to username@gmail.com, so if you add the service name when you sign up it's very easy to block unwanted traffic. It also tells you which service sold your email to spammers.
Unless the spammers simply run remove the extra part from the address. A better way is to get your own domain and use a different alias for each service.
I've been doing the + thing for more than 10 years now. My observation is that spammers simply don't remove it (it's just not worth their time).
More importantly, legit services that are on the spammy side (or have broken unsubscribe links) will absolutely never remove it.
Back a few years when Ameritrade had a bunch of its user's emails sold to spammers, I just changed my email on the ameritrade website and started blocking my +ameritrade address. It worked like a charm.
Thankfully, I never shared my genuine data with Facebook or opened an a/c on Instagram or Whatsapp ever so I'm good at a certain level when it comes to Facebook.
In my opinion Twitter is the only option that is sane at the moment.