Show inlined info about youtube links in erc buffers.
(require 'erc-youtube)
(add-to-list 'erc-modules 'youtube)
(erc-update-modules)
Or (require 'erc-youtube)
and M-x customize-option erc-modules RET
This plugin subscribes to hooks erc-insert-modify-hook
and
erc-send-modify-hook
to download and show images.