import re
from urllib.request import urlopen

url         = "http://www.hackthissite.org"
quotes      = []
quote_regex = re.compile(b"<blockquote>(.*?)</blockquote>")

while True:
    quote = quote_regex.search(urlopen(url).read())
    quote = quote.group(1).decode("utf-8")
    if quote not in quotes:
        quotes.append(quote)
        print(quote + "\n")