Hi there,
The End User License Agreement (EULA) changed after Trimble acquired SketchUp to remove commercial use from the “free” version (SketchUp Make). Commercial use is still permitted with SketchUp Pro 2013 and Pro 2014, as well as SketchUp Pro 8 AND SketchUp 8 Free.
The new terms do not affect old versions of the software.
Current EULAs can be found here:
http://www.sketchup.com/license/b/sketchup-make
Doing a simple Ctrl+F with the word “commercial” will bring you to the appropriate section in the Make EULA.
I can get an official kudos from a team member, but if it counts, I interned at SketchUp for the past two summers!
Please let me know if anything I said was unclear or if I didn’t fully answer your question.
Thanks!