[Answer]-Two urls pointing to one view with optional parameter

You can pass extra arguments to your view functions like this:

url(r'^$', 'homepage', , {'signin': True}, name='homepage'),
url(r'^$', 'homepage', , {'signin': False}, name='signin'),

There is a third parameter in a URL pattern, which is a dict of arguments to pass straight to the view. So:

url(r'^signin/$',
    'homepage',
    {'signin': True},
    name='homepage'),