A crazy idea for Facebook home

I just thought of a crazy idea.

Facebook home displays updates from your facebook feed interspersed with adverts which make facebook money.

But why should facebook limit their feed to facebook? If they control and benefit from the ads on your home screen, why not add in feeds from other social networks as well still interspersed with ads that they control and benefit from? If consumers aren't visiting the website anyway (because of facebook home already does it for them) then why not make a bit of money from competitors as well? Then there would be less need for users to go to competitor's websites and Facebook still makes money.

What do you think? Would it work for them? Have I gone completely mad?