Docs: Link to pages that explain certain concepts

Close h5bp#1637

doc/css.md

@@ -11,8 +11,10 @@ HTML5 Boilerplate's CSS includes:
 * [Placeholder media queries](#media-queries)
 * [Print styles](#print-styles)
 
-This starting CSS does not rely on the presence of conditional class names,
-conditional style sheets, or Modernizr, and it is ready to use no matter what
+This starting CSS does not rely on the presence of
+[conditional class names](http://www.paulirish.com/2008/conditional-stylesheets-vs-css-hacks-answer-neither/),
+[conditional style sheets](http://css-tricks.com/how-to-create-an-ie-only-stylesheet/),
+or [Modernizr](http://modernizr.com/), and it is ready to use no matter what
 your development preferences happen to be.
 
 

doc/faq.md

@@ -50,8 +50,9 @@ A list of more complex HTTP servers can be found
 ### Why don't you automatically load the latest version of jQuery from the Google CDN?
 
 The [file](https://ajax.googleapis.com/ajax/libs/jquery/1/jquery.js) to which
-the Google CDN points to is [no longer updated and will stay locked at version
-`1.11.1` in order to prevent inadvertent web
+the Google [CDN](https://en.wikipedia.org/wiki/Content_delivery_network) points
+to is [no longer updated and will stay locked at version `1.11.1` in order to
+prevent inadvertent web
 breakage](http://blog.jquery.com/2014/07/03/dont-use-jquery-latest-js/).
 
 In general, version updating should be an intentional decision! You shouldn't