yes of course. You can do whatever you want with your site as long as it abides by the country's laws that it is hosted in.
Sign up with google's adsense program if you are interested in offering advertising on your site.
Patron: I'd like my free lunch please.
Cafe Manager: Free lunch? Did you read the fine print stating it was an April Fool's joke.
Patron: I read the same way I listen, I ignore the parts I don't agree with. I'm suing you for false advertising.
Cafe Owner: Is our lawyer still working pro bono?