A bunch of minor doc/message fixes.

pub/docs/user/install.mdy

@@ -10,6 +10,26 @@ Urbit can be installed on most Unix systems.  There is no Windows
 port.  Windows is a wonderful OS, we just haven't gotten to it yet.
 Use a VM.
 
+## Configure the OS
+
+Urbit wants to map 2GB of memory when it boots up.  We won't
+necessarily use all this memory, we just want to see it.  On a
+normal modern PC or Mac, this is not an issue.  On some small
+cloud virtual machines (Amazon or Digital Ocean), the default
+memory configuration is smaller than this, and you need to
+manually configure a swapfile.
+
+To add swap to a DO droplet:
+
+https://www.digitalocean.com/community/tutorials/how-to-add-swap-on-ubuntu-14-04
+
+To add swap on an Amazon instance:
+
+http://stackoverflow.com/questions/17173972/how-do-you-add-swap-to-an-ec2-instance
+
+Don't spend a lot of time tweaking these settings; the simplest
+thing is fine.
+
 ## Install as a package
 
 ### OS X - Homebrew

pub/docs/user/launch.mdy

@@ -6,7 +6,7 @@ next: true
 
 # Launch procedure
 
-An urbit is a persistent server on the `%ames` P2P network.
+An urbit is a persistent server on the Urbit P2P network.
 You'll create one of these servers now.  To understand what
 you're building, you need to know a little about the network.
 
@@ -31,8 +31,8 @@ the miscellaneous true facts below:
 
 ## Network architecture
 
-An Urbit address is a 128-bit number, or *plot*.  Every server on
-the Urbit network (or just an "urbit") has one unique plot.
+An Urbit address is a number, or *plot*, under 2^128.  Every
+server on the Urbit network has one unique plot.
 
 Since Urbit is designed as a personal server, a plot is both a
 network address and a digital identity.  There is no additional