Kind of important if you’re using any version of ArchiCAD and getting excited about Lion (or have already installed it). Read it. Now:
No more using any version of ArchiCAD older than version 10 if you go to Lion (Mac OS 10.7). Good to know for all those 8.1 and 6.5 files I occasionally need to open. If you don’t have ArchiCAD 10, remember to install the file converters so you are prepared.