The internet is great at eliminating the middlemen. One only needs to look at the music industry to see one of the fiercest battles for survival being waged by fat lazy middlemen anywhere. The middlemen in that industry, of course, are the record companies. In an age where musicians (and their fans) can effectively market, distribute and monetize their goods (music) using online tools (many of them free), there really is no need to have record companies. Record companies used to play a role. They are now obsolete.
Advertising used to play a role. Before the internet, the only effective way to reach your potential customers was through advertising. If you launched a new product, how else would anyone find out about it? Word of mouth existed, but was ineffective, with very very low viral coefficients.
But the internet changes that. Search engines are very effective at matching demand with supply. I recently needed to buy pectin. All I had to do was type in "pectin" in Google, and one of the top results directed me straight to a manufacturer's website, where I found that the local Whole Foods stocked the item. No advertising needed. When a hot new product launches, I hear about it in blogs, and my friends talk about it, share items, post tweets, IM links, email articles. Again, no advertising needed.
Of course, there's the inconvenient truth. Advertising can't die, because advertising still makes money. The odd thing is, advertising doesn't make money because consumers demand it. I don't know of anyone who likes ads. No, advertising lives because of inertia. These companies have paid billions of dollars in advertising for decades. Why would they stop? Most of them don't know, for example, that improving your search ranking and paying top dollars for AdWords yield the same results, except the latter costs money. Surely, if it costs money it must be better (you know, the same way free Open Source software couldn't possibly be as good as multi-million dollar enterprise software). Sooner or later, the beast will die. Question is, what comes next? *shrug* I just wanted to rant against ads.