--- a/web-seo.rst	Sat Aug 06 00:07:09 2016 +0300
+++ b/web-seo.rst	Sat Aug 06 23:53:20 2016 +0300
@@ -6,17 +6,136 @@
 .. contents::
    :local:
 
-Informing search engine about site structure.
-=============================================
+General search engines
+======================
+
+Major search engines are:
+
+* https://google.com from Google Co.
+* https://bing.com from Microsoft Co.
+* https://yahoo.com or https://search.yahoo.com/ from Yahoo Co and it uses Bing
+  engine.
+
+Major local search engine are:
+
+* https://yandex.com from Yandex Co that have large market on Russia, Ukraine, Belarus.
+
+SEO tips
+========
+
+* Use pain text rather than images, CSS, JavaScript, Flash, SilverLite or other
+  technologies for important content.
+
+* Make sure your site work without with CSS, JavaScript, Flash, Java, etc
+  disabled. Check your site with screen reader or text browser (lynx, w3m).
+
+* Avoid HTML frames and iframes.
+
+* Market your site so other sites link to yours.
+
+* Tend to focus on single topic per page.
+
+* Avoid cryptic URLs. Craft human attractive URLs as URL words directly can be
+  indexed. Use dashes instead of spaces.
+
+* Shutdown mirrors or use ``link rel="canonical"`` tag to point to page on main
+  site.
+
+https://support.google.com/webmasters/answer/139066
+  Use canonical URLs
+https://en.wikipedia.org/wiki/Canonical_link_element
+  Wiki article.
+
+Informing search engine about site structure
+============================================
 ::
 
   http://www.example.org/sitemap.xml
   http://www.example.org/robots.txt
 
- * http://en.wikipedia.org/wiki/Sitemaps
- * http://www.sitemaps.org/
- * http://en.wikipedia.org/wiki/Robots.txt
- * http://www.robotstxt.org/
+robots.txt
+==========
+
+Start line with ``#`` to commet it out.
+
+Disable all robots (that respect ``robots.txt``)::
+
+  User-agent: *
+  Disallow: /
+
+To allow all robots complete access::
+
+  User-agent: *
+  Disallow:
+
+To allow a single robot::
+
+  User-agent: Google
+  Disallow:
+
+  User-agent: *
+  Disallow: /
+
+All valuable search engines support ``Allow`` and ``Sitemap`` tags::
+
+  User-agent: *
+  Allow: /
+  Sitemap: http://example.com/sitemap1.xml
+  Sitemap: http://example.com/my_sitemap2.xml
+
+The longer path the higher priority of ``Allow`` and ``Disallow`` tags.
+
+
+http://www.robotstxt.org/orig.html
+  Original specification. Only ``User-agent`` and ``Disallow`` tags supported.
+http://robotstxt.org.ru/
+  Russian followup to http://www.robotstxt.org
+https://developers.google.com/webmasters/control-crawl-index/docs/robots_txt
+  Google extension specification.
+https://yandex.ru/support/webmaster/controlling-robot/robots-txt.xml
+  Yandex extension specification.
+http://en.wikipedia.org/wiki/Robots.txt
+  Wiki article.
+
+meta robots
+===========
+
+Instruction to not index current page::
+
+  <meta name="robots" content="noindex">
+
+Instruction to not follow links on current page::
+
+  <meta name="robots" content="nofollow">
+
+Pair combinations::
+
+  <meta name="robots" content="noindex, nofollow">
+  <meta name="robots" content="noindex, follow">
+  <meta name="robots" content="index, nofollow">
+  <meta name="robots" content="index, follow">
+
+rel nofollow attribute in link
+==============================
+
+To prevent spam on forums and blogs or to including commertial links::
+
+  <a href="http://spam.com/sale/20-off" rel="nofollow">You win 100$!!</a>
+
+https://support.google.com/webmasters/answer/96569
+  Use rel="nofollow" for specific links.
+https://support.google.com/webmasters/answer/81749
+  Ways to Prevent Comment Spam.
+https://en.wikipedia.org/wiki/Nofollow
+  Wiki article.
+https://codex.wordpress.org/Nofollow
+  Wordpress suggestions.
+
+sitemap
+=======
+
+* http://en.wikipedia.org/wiki/Sitemaps
+* http://www.sitemaps.org/
 
 Alexa.
 ======