Adds lots of Mojo documentation

services/README.md

-Chrome Foundation Services
-====
+# Chrome Foundation Services
 
-### Overview
+[TOC]
+
+## Overview
 
 This directory contains Chrome Foundation Services. If you think of Chrome as a
 "portable OS," Chrome Foundation Services can be thought of as that OS'
 foundational "system services" layer.
 
 Roughly each subdirectory here corresponds to a service that:
 
   * is a client of `//services/service_manager` with its own unique Identity.
   * could logically run a standalone process for security/performance isolation
     benefits depending on the constraints of the host OS.
 
-### Service Directory Structure
+## Service Directory Structure
 
 Individual services are structured like so:
 
-    //services/foo/                   <-- Implementation code, may have subdirs.
-                  /public/
-                         /cpp/        <-- C++ client libraries (optional)
-                         /interfaces/ <-- Mojom interfaces
+```
+//services/foo/                   <-- Implementation code, may have subdirs.
+              /public/
+                     /cpp/        <-- C++ client libraries (optional)
+                     /interfaces/ <-- Mojom interfaces
+```
 
-### Dependencies
+## Dependencies
 
 Code within `//services` may only depend on each other via each other's
-`/public/` directories, i.e. implementation code cannot be shared directly.
+`/public/` directories, *i.e.* implementation code may not be shared directly.
 
 Service code should also take care to tightly limit the dependencies on static
 libraries from outside of `//services`. Dependencies to large platform
 layers like `//content`, `//chrome` or `//third_party/WebKit` must be avoided.
 
-### Physical Packaging
+## Physical Packaging
 
 Note that while it may be possible to build a discrete physical package (DSO)
 for each service, products consuming these services may package them
 differently, e.g. by combining them into a single package.
 
-### Documentation
+## Additional Documentation
 
 [High-level Design Doc](https://docs.google.com/document/d/15I7sQyQo6zsqXVNAlVd520tdGaS8FCicZHrN0yRu-oU)
-[Homepage](https://sites.google.com/a/chromium.org/dev/servicification)
 
-### Relationship to other top-level directories in //
+[Servicification Homepage](https://sites.google.com/a/chromium.org/dev/servicification)
+
+## Relationship To Other Top-Level Directories
 
 Services can be thought of as integrators of library code from across the
-Chromium repository, most commonly //base and //mojo (obviously) but for each
-service also //components, //ui, etc in accordance with the functionality they
-provide.
+Chromium repository, most commonly `//base` and `//mojo` (obviously) but for
+each service also `//components`, `//ui`, *etc.* in accordance with the
+functionality they provide.
 
-Not everything in //components is automatically a service in its own right.
-Think of //components as sort of like a //lib. Individual //components can
-define, implement and use mojom interfaces, but only //services have unique
-identities with the Service Manager.
+Not everything in `//components` is automatically a service in its own right.
+Think of `//components` as sort of like a `//lib`. Individual `//components` can
+define, implement and use Mojom interfaces, but only `//services` have unique
+identities with the Service Manager and so only `//services` make it possible
+for Mojom interfaces to be acquired.
 
-### Adding a new service
+## Adding a new service
 
-Please start a thread on [services-dev](https://groups.google.com/a/chromium.org/forum/#!forum/services-dev)
+See the [Service Manager documentation](/services/service_manager) for more
+details regarding how to define a service and expose or consume interfaces to
+and from other services.
 
+Please start a thread on [services-dev@chromium.org](https://groups.google.com/a/chromium.org/forum/#!forum/services-dev)
+if you want to introduce a new service.