An introduction to chat channels

[Niwashi]

2. /blist add <r>. Or, in general, the fact that <r> expands to the name of the last person to send you a tell. It's just that this is the most common use for it, and it makes for a handy macro on servers that are really plagued with RMT spam.

This was extremely useful before patch 2.1, but now that we can just right click a name in chat (or on consoles, select the name and press X) to get a Blacklist option, the usefulness of "/blist add <r>" has dropped significantly.