The functionality for poster highlighting / ignoring has been tied to the user login rather than the cookie on individual machines. This will also allow us to track how many users are highlighted or ignored, which gives us an idea about how the community is functioning.
The bad news is you're going to have to re-do all your highlighted and ignored posters. The good news is when you log in to a session, your highlights and ignores should automatically get applied.
To highlight or ignore a poster, just click the link inside a post the way you do today. You have to be logged in to do it.
To un-highlight a poster, go to the "Manage My Account" link, where your highlights will be listed and you can un-highlight as many as you want. You can also do this to un-ignore someone, but the option to do that on the boards remains.
Might be a bump or two while we sort the whole thing out, but it's up and running now.