Why SEO is Necessary
Google has pretty much always frowned on SEO. Every time a trash site pops up on page one for a competitive keyword, it makes Google look bad, and they have to invest more money into updating their algorithms and diverting resources to manual reviews.
This isn't to say that all 'SEO' is evil. The problem is that the industry is abused, with people building thousands of thin affiliate sites per day. Pros in the business have made a killing by building dozens or even hundreds of sites based on the buzz word of the week. It's a rinse and repeat process, and so far, Google hasn't been very good at punishing the people who seek these search engine loopholes.
Site owners need to draw the fine line between spamming and promoting. There is absolutely nothing wrong with promoting your website, if it's something worth visiting. Before you drop a comment on a widely visited blog, think to yourself, "Do the readers here stand to benefit from checking out my site or am I just trying to deliberately waste their time?"
Getting great exposure on the Internet is one of the few ways that people and small businesses can level the playing field and it's a shame that 'black hat' techniques such as spamming and site cloaking have given the industry such a bad rep.