My employer blocks access to ALL social media sites from company computers, including Linked In, Twitter, Facebook, Reddit, etc. I work from home so I can peruse anything I want on my personal computer or cell phone and not let them block things or see what I do that isn't company business.
However, they routinely distribute emails to everyone with marketing announcements, press releases, etc. which the company posts to their official Linked In or Twitter feeds, with links to them. They're now sending them with an additional email from an executive asking that any employee who is on those platforms please interact with and cross post the company posts being sent to us.
As if. I'm not going to use my personal computer or device, and social media accounts, to advertise for you. Especially when you prohibit access to those sites on the work computer.