Updated Does µBlock blocks ads or just hide them? (markdown)

Does-µBlock-blocks-ads-or-just-hide-them?.md

@@ -1 +1,45 @@
-.
+I've seen an increase in misrepresentation and disinformation lately regarding µBlock -- and not surprisingly always from anonymous sources.
+
+I will set the official record here.
+
+There seems to be underhanded attempts to discredit µBlock lately in various venues. Here is a typical comment: ： 
+
+> uBlock who is recently found to not actually "block" ads, but rather hide them after its been displayed. Adblock actually blocks them before they can even display them.
+
+The statement above is plain fear-using-disinformation. That kind of disinformation happens to be convenient to the incumbent blockers, **or** to those who have an interest in people using those incumbent blockers.
+
+There are two kinds of [ABP-compatible filters](https://adblockplus.org/en/filters): network filters and cosmetic filters. _Cosmetic filters_ are referred to as _element hiding_ filters by Adblock Plus ("ABP").
+
+#### Network filters
+
+**Short answer:** resources blocked: network requests are cancelled before they leave the browser.
+
+The purpose of network filter is to prevent a network request to be made to a remote server, so as to prevent downloading a remote resource. µBlock will prevent the network request from even being made. This saves bandwidth, decrease privacy exposure -- as the remote server won't be able to log anything if you do not contact it.
+
+#### Hosts file
+
+**Short answer:** resources blocked: network requests are cancelled before they leave the browser.
+
+µBlock also support the parsing and enforcing of hosts files -- something which ABP does not. All entries in a hosts file are parsed as network filters, i.e. no resource will be fetch from a remote server which appear in a hosts file, no connection will even be attempted.
+
+#### Cosmetic filters
+
+**Short answer:** resources hidden -- in various ways depending on the class of cosmetic filters.
+
+These filters serve to remove DOM elements from a web page. They have no value privacy-wise, it is essentially to make web page look better by removing unwanted content, which usually cannot be blocked using network filters. Just like ABP, µBlock will hide DOM elements on a web page which match cosmetic filters. µBlock uses a [different method](https://github.com/gorhill/uBlock/wiki/Cosmetic-filtering-in-%C2%B5Block:-version-0.4.0.0-update) than other big-name blockers to hide the DOM elements though.
+
+Different classes of cosmetic filters are applied differently:
+
+- Specific cosmetic filters: injected before page's root DOM is loaded
+    - No flickering
+- Generic cosmetic filters: injected after page's root DOM is loaded
+    - These are cacheable
+    - Since these cosmetic filters are applied after page load, DOM elements **may** be hidden after they are rendered
+    - Notice the emphasized "may": generally, you won't see this; and sometimes you will notice **more** flickering with ABP (with same filter lists):
+    - Demonstration: [test page](http://raymondhill.net/ublock/tiles1.html)
+        - Chromium + uBlock: minimal flickering (sometimes none)
+        - Chromium + ABP: noticeable flickering
+        - Firefox + uBlock: no flickering
+        - Firefox + ABP: no flickering
+- Cached generic cosmetic filters: injected before page's root DOM is loaded
+    - No flickering