revised version of ripper234's script

#!/usr/bin/python2.7

import re
import sys
import sys
import datetime

from urllib2 import urlopen

# count how many lines in a file
def file_len(fname):
    with open(fname) as f:
        for i, l in enumerate(f):
            pass
    return i + 1

input_file = './input.txt'
input_file_length = file_len(input_file)
f = open (input_file)
list = []

print "Fetching pages..."

for i, line in enumerate(f):
    sys.stdout.flush()
    line = line.strip()
    m = re.search('\* <(htt.*?)>(.*)$', line)
    if (not m):
        print "Failed to match line '{}'".format(line)
    sys.exit()

    site = {}
    site['url'],site['description'],site['questions'],site['users'],site['answers'] = m.group(1), m.group(2),0,0,0
    print "{}/{} ({}) - Fetching data from {}".format(i+1, input_file_length, datetime.datetime.now(), site['url'])

    # go get one site
    try:
        html = urlopen(site['url'], timeout = 60).read()
    except Exception as e:
        print "Problem fetching URL {}: {}".format(site['url'], e)
        continue

    # got the site. Search for the number of questions, and the number of answers, in it
    m = re.search('<div class="questions-count">\s*(\d+)\s*<.*<div class="questions-count">\s*(\d+)\s*<', html)
    # and get the page title, to use as a description, in case we don't already have a description for this site
    m1 = re.search('<title>\s*(.+)\s*</title', html)
    if (not m):
    print "Failed to find question count for", site['url']
    else:
        # yay - we have a number of questions and answers - save them for this site
    site['questions'] = int(m.group(1))
    site['answers'] = int(m.group(2))
    if ((site['description']=="") & (not not m1)):
        site['description']=m1.group(1)


    print "Found {} questions".format(site['questions'])

    try:
        # now try to get the number of users. By default there are 35 users per page
        html = urlopen(site['url']+'users/', timeout = 60).read()
    m2 = re.search('>\s*(\d+)\s*</a><span class="next">', html)
    if (not m2):
        print "Failed to find 'next page' tag for {}, assuming just 1 page of users".format(site['url'])
        site['users']=1
    else:
        site['users']=int(m2.group(1))

    print "Found {} pages of users".format(site['users'])

    except Exception as e:
        print "Problem fetching URL {}/users/: {}".format(site['url'], e)
        site['users']=0

    list.append(site)

# and now we've cycled through all our sites
print
print "The sorted list:"
print

# sort them into descending order by number of questions
list.sort(key = lambda x:x['questions'])
list.reverse()
# and finally, output the list of sites
for site in list:
    print " * <{}> ({} questions, ".format(site['url'], site['questions']) + "{}-{} users".format(site['users']*35-34,site['users']*35) + ") {}".format(site['description'])