(Thought I'd posted this reply earlier, but I don't see it in the list;
sorry if I'm posting a duplicate here.)

Kelvin White <kwhite@gnu.org> writes:

> Hi Keivn, I have a few questions about this...
> Can you elaborate on the use case here a bit more? What do you mean by
> 'keying on the server'

The key in the assoc list is typically something like "freenode\\.net"
(a regex matching the IRC server).

I use ERC to connect to my Weechat IRC proxy; the same proxy *server*
provides access to several *networks*, but the
`erc-server-announced-name' is always "weechat.ssl.irc" (more info at
https://weechat.org/files/doc/stable/weechat_user.en.html#relay_irc_proxy
). The only way I've seen to differentiate is by the value of
`erc-network' (well, also each server buffer contains a string like
NETWORK=freenode or NETWORK=BitlBee, I suppose that's how `erc-network'
is set).

> What version of emacs are you using with this?

24.4.1

-- 
Kevin Brubeck Unhammer

GPG: 0x766AC60C