User blog comment:Cristina7/Introducing Discussions, a New Platform For Engaging Your Community/@comment-31952814-20160909071758/@comment-5275700-20160910021125

To be very clear -- both local and global blocks (on usernames and IPs) are effective in Discussions. There were some cases where local IP blocks were not effective, but this has been resolved.

We'll be improving the messaging to locally blocked users, when they try to post, the coming weeks. They'll be seeing the block reason, etc.

Globally blocked users are not able to initiate any type of action in Discussions.