Well you obviously need more views per day than Twitter & Facebook a year ago (not sure when they broke through the profit barrier)
ALternatively you could easily get to $'00s or $'000s per month on free hosting - e.g. a Blogspot or WP.com blog.
People have TV and Book deals based upon twitter accounts.
You could easily make a 6 figure income using Blogspot to host a sales page and eJunkie for sales and product delivery.
With Adsense you can easily have between $0.10 and $100 CPM (per thousand views) even if you only make $0.10 to $0.20 per click.
My first niche website many moons ago (well 5 years or so) I was making $0.05 to $0.10 per visitor in a gardening niche. So you could break even with paid hosting at 3 visitors per day.