Currently I am working on a research paper about the OpenStreetMap evolution of Germany. For the last AGIT conference in Salzburg and the upcoming State of the Map Europe (SotM-EU) conference in Vienna I did a similar analysis about the OpenStreetMap Evolution of Austria. You can see the results in the following posters in English and German:

The OpenStreetMap Evolution of Austria (2007–2011)

Die OpenStreetMap Entwicklung in Österreich (2007–2011)

A further nice visualization of the OpenStreetMap data in Austria for the year 2010, can be found in a blog post by Max Kossatz.