I am thinking about 'mass' building websites for people. I don't want to get into the specifics of what exactly I may do, but I'm wondering is there a problem with having adsense on a domain & website I don't own? Obviously, there may be an issue w/ the person I'm building the site for but I'm just wondering about any possible problems (TOS) specifically with AdSense. My ultimate goal would be to have upwards of 100+ sites if that makes a difference.