(C-c C-j runs the command erc-join-channel)

connected to freenode, joined #python.web.  c-c c-j #python did
nothing, no errors, but no new buffer and no change either.  c-c c-j
#pylons however did create a new buffer with the #pylons channel in
it.

Some googling pointed out:
http://www.nabble.com/Official-IRC-channel-for-Python--td15660847.html
that one needs a registered nick to join #python; the python-list
thread suggests that other clients actually tell you that on failure,
so erc probably should too.

Dear submitter,

as the package erc has just been removed from the Debian archive
unstable we hereby close the associated bug reports.  We are sorry
that we couldn't deal with your issue properly.

For details on the removal, please see https://bugs.debian.org/836579

The version of this package that was in Debian prior to this removal
can still be found using http://snapshot.debian.org/.

This message was generated automatically; if you believe that there is
a problem with it please contact the archive administrators by mailing
ftpmaster@ftp-master.debian.org.

Debian distribution maintenance software
pp.
Chris Lamb (the ftpmaster behind the curtain)