more work on the intro text of 'working with data' section

src/pages/build/guide/index.md

@@ -12,10 +12,9 @@ This Build Guide organizes everything you need to know about developing Holochai
 
 ## Working with data
 
-Shared data in a Holochain application is stored as a graph database of **entries** connected by **links**.
+Shared data in a Holochain application is stored as a graph database of **entry** nodes connected by **links**, plus a couple special types of data that can also be treated as nodes in the graph:
 
-An **action** is a third type of data. It records the act of manipulating an entry or link and contains metadata about the act, such as authorship and timestamp. It can also be treated as a primary piece of graph data, similar to an entry.
-
-Finally, an **agent ID** is the public identifer of a participant in an application, and is an honorary piece of graph data that links can point to and from.
+* An **action** records the act of manipulating an entry or link and contains metadata about the act, such as authorship and timestamp.
+* An **agent ID** is the public key of a participant in an application.
 
 * [Entries](entries/)