Globally ignored users may still post, they can be followed, and their posts can be shared. However, Hubski won't include them in content discovery.
Importantly, this 'global ignore' is not simply based upon the number of users ignoring an account. It also considers other metrics of user activity and appreciation. As a result, it would be very difficult to cause a legitimate user to be dropped from the external posts by ignoring the account.
Of course, I can't say exactly what metrics are used to separate heavily-ignored users from spammers, but I will monitor the global ignore list and ensure that it isn't being inappropriately applied.
As always, feedback is much appreciated.
BTW, you can see the list of those users that you ignore under 'controls'.