You are not ignoring any users at the current time.
This page lets you configure filters that keep unwanted messages out of your sight. There are two distinct mechanisms: one rejects all messages (both public and private) from users you name; the other filters out of the public Chatterbox any messages which match specific string patterns you define.
In the upper part of the page, you see a list of the users you are currently
The usual way to add a user to this list is by typing
/ignore usernamein the Chatterbox.
If there are any names listed here, there will be a link next to each one; clicking the link removes that user from your ignore list.
In the lower part of the page, there is a form for entering a list of string patterns. When viewing the Chatterbox, any message which contains any of the strings will not be displayed. In this way, you can effectively "ignore" messages which, for example, contain foul language.
The strings you want to filter on are entered all together in one text field, separated by commas. (This has the side effect of making it impossible to filter on comma, or any string containing a comma.)
Please note that the strings are taken literally; they are not regular expressions. Matching is performed case insensitively. (For the Perl inclined, it is equivalent to embedding each string $s in /\Q$s\E/i.)