Add a discussion of the blank lines in .sbt files; realized everyone keeps mentioning this but "getting started" barely did

Getting-Started/Getting-Started-Basic-Def.md

@@ -111,6 +111,22 @@ If you use the wrong value type, the build definition will not compile:
 ```scala
 name := 42  // will not compile
 ```
+### Settings are separated by blank lines
+
+You can't write a `build.sbt` like this:
+
+```scala
+// will NOT work, no blank lines
+name := "hello"
+version := "1.0"
+scalaVersion := "2.9.1"
+```
+
+sbt needs some kind of delimiter to tell where one expression stops and the next begins.
+
+`.sbt` files contain a list of Scala expressions, not a single Scala program. These expressions have to be split up and passed to the compiler individually.
+
+If you want a single Scala program, use [[.scala files|Getting Started Full Def]] rather than `.sbt` files; `.sbt` files are optional. [[Later on|Getting Started Full Def]] this guide explains how to use `.scala` files. (Preview: the same settings expressions found in a `.sbt` file can always be listed in a `Seq[Setting]` in a `.scala` file instead.)
 
 ## Keys are defined in the Keys object