[web2py] License Question

[SeamusSeamus]

Quick question:
 When do I need to have "powered by web2py" on the bottom of my page? For 
my own personal projects? If I charge to use my site / app? What if I run 
it on a clients server and manage it for them? What if I sell the software 
to a company? My clients will not want "Powered by Web2py" at the bottom of 
their page....am I reading this right?