To prevent seeing chat messages (including emotes) from another player. You can use the Ignore Player button in the Socials window to add a player character to your ignore list.

Generally used when harassed, or just annoyed by someone.

The ignore list can only store 50 names maximum, increased from 25 with Patch 3.3.0. This can be expanded via AddOns (like IgnoreMore), but new ignores may not have the same functionality.

Slash command usage

To ignore a player character:

/ignore name

/ignore name realm

To unignore a player character:

/unignore name

/unignore name realm

Notes

• To remove an Ignore, use Unignore.
• Player characters on your ignore list cannot be matched with you with the /lfd system.
• Player characters on your ignore list cannot ask to duel you.
• Player characters on your ignore list cannot send you mail.^[1]

Past changes

Patch 3.3.0 (08-Dec-2009): The amount of characters a person can ignore has been increased to 50. In addition, players on other realms can be placed on the Ignore list. 

See also

• Ignore List

References

1. ^ "Types of Mail" section of official Mail info