As you may have read the previous posts on creating search engine proof websites, designing naturally and providing value, I believe there was nothing about marketing, in this respect, on this blog. Not any more.
In the recent World Talk Radio interview with Matt Cutts (4th episode), Matt said something along the lines of "Google views advertising as another form of search. People are looking for information and Google helps them to find it.". This phrase started a peculiar train of thought on Internet marketing here.
For ad publishers
Though some may relate advertising as one of the ways to earn money by offering your audience to the advertiser, there is another point of view on advertising. You can try to present useful, quality and relevant advertising to your audience. This way give your visitors another way to actually use your website and find what they want. And you get the money from the ad publishers.
What to do, if you want some online advertising? If you focus on giving to your customers from the start, you'll know the basics already. If not, you need to find websites, where your most targeted audience roams. Try to provide value with your advertising to your target audience by informing them about an opportunity to improve their life and/or business, educate, entertain or amuse them.
You can also try to find websites, where your ad will have higher chances of providing value. Say, on a research website, where your ad will introduce your own research on the topic or present a tool to allow your potential customers to conduct their own researches.
Make your advertising something that those, who are adverse to advertising, will look at. Make your ads another piece of quality content your target audience (on other websites) will benefit from. And offer your product/service as a solution to your target audience need.
Essentially, you need to focus on knowing your customer and providing the best value to him/her. While this sounds simple, instead of barely nodding and continuing on publishing 'wow-designed' ads, do a thorough research on your customers and try to provide value with your online marketing efforts. You are bound to notice the difference.
Update: read more about optimizing the site for the humans.