Everywhere you go, someone is trying to sell and advertise their product. When you are browsing a page, an advertisement comes on, and most of the time it is ignored. I think that big business advertise to often. Whenever you watch television, the commercials run just as much as the program that you are watching!
The internet has made us numb to traditional forms of advertisement, and forced ad companies to innovate and come up with new strategies to sell their products. We saw the same thing with the advent of television. Overall, I do not think that this is a negative thing - advertising should have to keep up with its audience, after all.
I do think the internet has made us better at tuning out advertisements though. I think most of us are now totally capable of going about what we were going without really noticing the advertising that is being shoved in our faces. However, I do think most people notice a really well crafted ad, despite being bombarded all the time.
I do not think the internet has made people numb to advertisements they see. People still notice ads and care about them. I hear people talking about billboard and magazine ads all the time. Ads are everywhere and if we were to become numb to them, you cannot blame it all on the internet.