For example, if you want highly geo-targeted traffic, then offline easily equals organic SEO and paid search marketing. You can even make it more laser targeted if you like. Even the best PPC programs usually only get you down to city level -- at least in Australia. But with a local flyer run, you can go street by street. Sure, you'll be paying more for each click. But if being super-local increases the odds that you'll make sales (and it often does) then this extra cost is worth it.
There's another scenario in which offline promotion of a website can be excellent: That's if you offer internet-related services, but you want to target people who are not heavily into the net.
This site is an example. I show Perth locals how to use social media sites like Twitter, Facebook and Google Plus. Of course it's worth sharing details of my classes on these very sites because the more people who know about them the better. And someone who's learned about me this way might tell a friend or colleague.
Still, its extremely unlikely that I'm going to get leads directly from, say, Twitter. That's because if they're on that site already they don't need to be taught how to use it.
There must be lots of other net-centric products and services in which this same situation applies. Technical trouble shooting and PC hardware repair come to mind. After all, if someone's computer is broken they won't be able to surf the net for someone to repair it! But if they receive a flyer in their letterbox at such a time they'll be very pleased to get it and highly likely to call the number provided.
Other services that are heavily used by business and industry such as web hosting, cloud computing and business management software can also be effectively promoted offline. Flyer drops focusing on industrial areas can be very effective.