Document more on what APacheDEX is and is not.

Also, italicise -h and --help.

README

@@ -3,26 +3,47 @@ Compute APDEX from Apache-style logs.
 Overview
 ========
 
-Parses Apache-style logs and generates several statistics useful to website
-developers:
+Parses Apache-style logs and generates several statistics intended for a
+website developer audience:
 
 - APDEX (Application Performance inDEX, see http://www.apdex.org) ratio
   (plotted)
 
+  Because you want to know how satisfied your users are.
+
 - hit count (plotted)
 
+  Because achieving 100% APDEX is easy when there is nobody around.
+
 - HTTP status codes, with optional detailed output of the most frequent URLs
   per error status code, along with their most frequent referers
 
+  Because your forgot to update a link to that conditionally-used browser
+  compatibility javascript you renamed.
+
 - Hottest pages (pages which use rendering time the most)
 
+  Because you want to know where to invest time to get highest user experience
+  improvement.
+
 - ERP5 sites: per-module statistics, with module and document views separated
 
+  Because module and document types are not born equal in usage patterns.
+
 Some parsing performance figures:
 
 On a 2.3Ghz Corei5, apachedex achieves 97000 lines/s (
 pypy-c-jit-62994-bd32583a3f11-linux64) and 43000 lines/s (CPython 2.7).
 
+What APacheDEX is not
+=====================
+
+APacheDEX does not produce website audience statistics like AWStats, Google
+Analytics (etc) could do.
+
+APacheDEX does not monitor website availability & resource usage like Zabbix,
+Cacti, Ganglia, Nagios (etc) could do.
+
 Requirements
 ============
 
@@ -68,7 +89,7 @@ The output is HTML + CSS + JS, so you need a web browser to read it.
 Usage
 =====
 
-A few usage examples. See embedded help (-h/--help) for further options.
+A few usage examples. See embedded help (`-h`/`--help`) for further options.
 
 Most basic usage::