Whenever I used the old Coventry mod, people soon noticed that x has disappeared altogether and will then say so in a thread.
If the mod could hide just "new" content from a user, so Tachy thinks he's being ignored and others think he's stopped posting; it would be better; but near impossible to implement. I've learned to live without such functionality, rather than mess about with ignores I just ban, getting rid of idiots is always better in the long run.
I also found that the troll cottoned on pretty quickly and I just got bombarded with dupe account attempts instead. So for me not a really useful feature. Same as the "Annoy User" plugin which xenfor has in the core as discouraging.
Although with discouraging you can at least do it via IP, however most persistent trolls aren't going to stick to a static IP anyway.
Just to elaborate on this, we've been reviewing our [TH] Global Ignore add-on and have rebuilt much of it to improve the quality. Currently that add-on only allows you to moderate posts from ignored users, which isn't what most admins want from what I've seen. We've added an "Ignore type" field with the following options:
Ignore all content by ignored user
Ignore new content by ignored user
Moderate content by ignored user
This option is set per user and you can set the default selected value in your board options, it also will have an option of whether or not to show hidden content to guests (The default value is for this content to be displayed as guests so the user isn't able to logout and see that they've been blocked, but this can be changed as necessary). We should have something ready fairly soon