diff --git a/Dynamic-URL-filtering.md b/Dynamic-URL-filtering.md
index 8247568..8b8cb4d 100644
--- a/Dynamic-URL-filtering.md
+++ b/Dynamic-URL-filtering.md
@@ -8,7 +8,22 @@ URL filtering is accessible from the logger, i.e. you will create and manage dyn
 
 ![a](https://cloud.githubusercontent.com/assets/585534/7814025/5bf1df88-038d-11e5-9956-ecd3f56efeb0.png)
 
-URL filtering uses _rules_, which resemble dynamic filtering rules, except that the destination hostname is replaced by a URL.
+URL filtering uses _rules_, which resemble dynamic filtering rules, except that the destination hostname is replaced by a URL:
 
-A resource matches a URL filtering rule if the URL of the resource starts exactly with a given URL filtering rule.
+    [source hostname] [destination URL] type action
 
+`source hostname` is the _context_ from which a request is fired, and just like with dynamic filtering rules, the hostname of the URL in the address bar is used to determine the context. The global context (`*`) can be used to create a URL filtering rule which applies everywhere.
+
+`destination URL` is URL to match: the URL of a resource must **start exactly** with the `destination URL` of a rule for a match to occur.
+
+`type` is the type of a resource.  The special type `*` can be used to create a URL filtering rule which applies to any type of resource.
+
+`action` tells the URL filtering engine what to do when there is a match. Same as with dynamic filtering rules: `allow`, `noop` or `block`.
+
+It is very important to understand that URL filtering rules override dynamic filtering rules and static filtering rules. So you could create an `allow` URL filtering rule which override a `block` plain dynamic filtering rule.
+
+Examples of URL filtering usefulness.
+
+Un-break a web site: a real case was reported in [issue #240](https://github.com/gorhill/uBlock/issues/240). The web site required the resource `http://s7.addthis.com/js/300/addthis_widget.js` for the comment section to render properly. However, `s7.addthis.com` is blocked by uBlock's _Privacy_ filter list with an `important` filter, meaning the filter cannot be overriden by an exception filter. [URL filtering to the rescue](https://github.com/gorhill/uBlock/issues/240#issuecomment-105019619), since URL filtering override everything other kind of filtering rules.
+
+Finer-grained dynamic filtering: block all 3rd resources by default using dynamic filtering rule `* * 3p block`, but allow one very specific 3rd-party resource `example.com https://example.org/widget.js script allow`, something which would not be possible before URL filtering was available.
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