update README

README.md

@@ -1,4 +1,42 @@
 sent
 ====
 
-A simple plaintext presentation tool
+A simple plaintext presentation tool.
+
+sent does not need latex, libreoffice or any other fancy file format, it uses
+plaintext files. Every line represents a slide in the presentation. This may
+limit the use, but for presentations using the Takahashi method this is very
+nice and allows you to write down the presentation for a quick lightning talk
+within a few minutes.
+
+The presentation is displayed in a simple X11 window colored black on white for
+maximum contrast even if the sun shines directly onto the projected image. The
+content of each slide is automatically scaled to fit the window so you don't
+have to worry about alignment. Instead you can really concentrate on the
+content.
+
+Usage
+-----
+
+	sent [-f FONTSTRING] FILE1 [FILE2 ...]
+
+If one FILE equals `-`, stdin will be read. A presentation file could look like
+this:
+
+	sent
+	why?
+	easy to use
+	few dependencies (X11)
+	no bloat
+	how?
+	sent FILENAME
+	thanks / questions?
+
+future features
+---------------
+
+* utf8 support
+* second window for speakers laptop (progress, time, notes?)
+* images
+* multiple lines per slide?
+* markdown?