This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
In the nbproject (short for "NetBeans Project") folder NetBeans saves some configuration-stuff for profiling-settings, build-scripts, etc. So you shouldn't remove it if you want to continue NetBeans as your IDE. (Even though it's good practice to have a build script which is independent from your IDE)