I don't run Linux myself so I'm afraid I'm not going to be much help. You should be seeing your default webbrowser being opened with a url. I know nothing about configuring a default webbrowser under Linux (google may be your friend). Perhaps a proxy issue?
If you put these two lines into a test.py file
Code:
import webbrowser
webbrowser.open('http://www.goodreads.com/')
Then type the equivalent of this from a shell prompt (I don't know if/how this varies for linux, I'm a Windows guy):
Code:
calibre-debug -e test.py
If that works, there should be no reason why the authentication page for goodreads shouldn't work. There is another option I have for opening the web pages using some Calibre wrapped code rather than python directly. Tell me if this works for you in comparison to the above:
Code:
from calibre.gui2 import open_url
from PyQt4.Qt import QUrl
open_url(QUrl('http://www.goodreads.com/'))