--- a/rdf-primer/index.html	Mon Feb 03 16:45:16 2014 +0100
+++ b/rdf-primer/index.html	Mon Feb 03 23:10:45 2014 +0100
@@ -130,10 +130,10 @@
 <section id="section-Introduction">
     <h2>Introduction</h2>
 
-    <p class="note">The objective of this document is to give a light-weight overview of RDF 1.1.
+    <p class="note">Thys document gives a light-weight overview of RDF 1.1.
     Secs. 3-5 can be used as a minimalist introduction into the key
     elements of RDF. Changes between RDF 1.1
-    and RDF 1.0 (2004 version) are summarized in the separate document "What's New in RDF
+    and RDF 1.0 (2004 version) are summarized in a separate document: "What's New in RDF
     1.1" [[RDF11-NEW]].</p> 
       
     <p>The Resource Description Framework (RDF) is a framework for
@@ -257,7 +257,7 @@
     three elements they are called <strong>triples</strong>.
     </p>
     
-    <p>RDF allows us to make statements of the form:</p> 
+    <p>Here are examples of RDF triples:(</p> 
 
     <pre class="example" id="example-1">
       &lt;Bob&gt; &lt;is a&gt; &lt;person&gt;.
@@ -292,6 +292,10 @@
       <figcaption>Informal graph of the sample triples</figcaption>
     </figure>
 
+   <p>Once you have a graph like this you can use SPARQL [[SPARQL11-OVERVIEW]] to
+    query for e.g. people interested in paintings by Leonardo da
+    Vinci.</p>
+
     <p>The RDF Data Model is described in this section
     in the form of an "abstract syntax", i.e. a data model that is independent of a
     particular concrete syntax (the syntax used to represent triples stored in
@@ -323,8 +327,8 @@
 
     <p>IRIs can appear in <strong>all three positions</strong> of a triple. </p>
 
-    <p>IRIs are used to identify resources such as documents,
-    physical, people, physical objects, and asbttact concepts.  
+    <p>As mentioned, IRIs are used to identify resources such as documents,
+    people, physical objects, and asbttact concepts.  
     For example, the IRI for the "Mona Lisa" painting in
     <a href="http://www.wikidata.org/">Wikidata</a> is:</p>
 
@@ -341,8 +345,8 @@
 
     <p>IRIs are global identifiers, so other people can re-use this
     IRI to identify the same thing. For example, the following IRI is
-    used by many people as an RDF property to state a friendship
-    relationship:</p>
+    used by many people as an RDF property to state an acquaintance 
+    relationship between people:</p>
 
     <div class="example"><a href="http://xmlns.com/foaf/0.1/knows">http://xmlns.com/foaf/0.1/knows</a></div>
       
@@ -424,7 +428,7 @@
       <p>RDF provides a mechanism to group RDF statements in multiple
       graphs and associate each graph with an IRI . Multiple graphs are a recent extension of the RDF
       data model. In practice, RDF tool builders and data managers
-      needed a mechanism to talk about subsets of of a collection of
+      needed a mechanism to talk about subsets of a collection of
       triples. Multiple graphs were first introduced in the RDF query
       language SPARQL. The RDF data model was therefore extended with a notion of
       multiple graphs that is closely aligned with SPARQL.</p>
@@ -484,6 +488,8 @@
       in the intended way. Possible semantics of datasets are described in a separate note
       [[RDF11-DATASETS]]. </p> 
 
+<p class="note">Consider adding a diagram of informal multiple graphs</p>
+
       <p><a href="#subsection-trig">Sec. 5.2</a> provides an example
     of concrete syntax for this example.</p>
 
@@ -626,6 +632,11 @@
   vocabulary</a>.</dd> 
 </dl>
 
+<p>Vocabularies get their value from reuse: the more vocabulary ITIs
+are reused by others, the more valuable it becomes to use the
+IRIs (the so-called netwrok effect). This means you should prefer
+re-using someone else's IRI instead of inventing a new one. </p>
+
 <p>For a formal specification of the semantics of the RDF Schema
 constructs the reader is referred to
 the RDF Semantics document [[RDF11-MT]]. Users interested in more comprehensive