Remove duplicate list from documentation

Users are prone to overread the introductory text and conclude that just because an extractor is missing in this list, youtube-dl does not support the site.

documentation.html

@@ -52,42 +52,10 @@
 <h1 id="d4">Supported sites</h1>
 
 <p>
-youtube-dl can download videos from a lot of sites, here's a list with some of the most popular.
-For a complete list, see the <a href="supportedsites.html">Supported sites</a> pages or execute <code>youtube-dl --list-extractors</code>.
+youtube-dl can download videos from not only YouTube, but over 150 different services.
+For a complete list, see the <a href="supportedsites.html">Supported sites</a> pages or execute <code>youtube-dl --extractor-descriptions</code>.
 </p>
 
-<ul>
-<li>YouTube.com.</li>
-<li>YouTube.com playlists (playlist URLs in "view_play_list" form).</li>
-<li>YouTube.com searches, using the special keyword "ytsearch" as a form of URL, as in "ytsearch:cute kittens". Do not forget the quotes if you want to include spaces in your search. Other variants are "ytsearchN" to download more than the first result, with N being a number, and "ytsearchall".</li>
-<li>YouTube.com user videos, using user page URLs or the specifc "ytuser" keyword.</li>
-<li>metacafe.com.</li>
-<li>Google Video.</li>
-<li>Google Video searches ("gvsearch" keyword).</li>
-<li>Photobucket videos.</li>
-<li>Yahoo! screen.</li>
-<li>Yahoo! screen searches ("yvsearch" keyword).</li>
-<li>Dailymotion.</li>
-<li>DepositFiles.</li>
-<li>blip.tv.</li>
-<li>vimeo.</li>
-<li>myvideo.de.</li>
-<li>The Daily Show / Colbert Nation.</li>
-<li>The Escapist.</li>
-<li>CollegeHumor.</li>
-<li>arte.tv.</li>
-<li>Soundcloud.</li>
-<li>xvideos.</li>
-<li>infoq.</li>
-<li>mixcloud.</li>
-<li>Stanford Open Content.</li>
-<li>Youku.</li>
-<li>MTV.</li>
-<li>XNXX.</li>
-<li>Google Plus.</li>
-<li>A generic downloader that works in some sites.</li>
-</ul>
-
 <h1 id="d5">Proxy support</h1>
 
 <p>youtube-dl supports downloading videos through a proxy, by setting the <em>http_proxy</em> environment variable to the proxy URL, as in <code>http://proxy_machine_name:port/</code>.</p>