Update README

README.md

 # BPFtrace
 
-BPFtrace is currently a work in progress and can not currently run scripts. The examples below are to give an idea of what the final result should be.
+BPFtrace aims to be a [DTrace](http://dtrace.org)-style dynamic tracing tool for linux, based on the extended BPF capabilities available in recent Linux kernels. BPFtrace uses [LLVM](http://llvm.org) to compile scripts to BPF-bytecode and many helper functions are included from [BCC](https://github.com/iovisor/bcc).
+
+BPFtrace's scripting language is inspired by [ply](https://github.com/iovisor/ply) and DTrace.
 
 ## Examples
 
+BPFtrace is a work in progress and can not currently run scripts. The examples below are to give an idea of what the final result should be.
+
 To produce a histogram of amount of time spent in the `read()` system call:
 ```
 kprobe:sys_read
@@ -19,6 +23,8 @@ kretprobe:sys_read / @start[tid] /
 ```
 
 ## Builtins
+The list of available builtins will grow as more features are added.
+
 The following builtin variables are available for use in BPFtrace scripts:
 - `pid` - Process ID
 - `tid` - Thread ID
@@ -40,7 +46,7 @@ The following builtin functions are also available:
 ## Compilation
 Compile using CMake, optionally substituting "Release" for "Debug" as CMAKE\_BUILD\_TYPE:
 ```
-git clone https://github.com/ajor/bpftrace.git
+git clone https://github.com/ajor/bpftrace
 cd bpftrace
 mkdir build
 cd build