Search Engine Optimization (SEO) Vs Content Optimization

Search Engine Optimization (SEO) Vs Subscriber Optimization which is the best? When we do research on making millions online, we always see people talking about following strategies for SEO (Search Engine Optimization).
I applied this concept  and based on my experience I believe that giving a well optimized post(content optimization)  helps us retain our user base in long run.
When Google launched its Adsense program, people started pouring in money, created a business model, did some SEO, launched their website. But many of them couldn't sustain. Following are some of the factors that contribute to the failure of such progeams:
1) They didn't update the content regularly
2) They created a website with say 100 posts. All of a sudden they didn't blog. This lead to a drastic hit in their page ranking. It is often essential to do consistent blogging to attain a good page rank and retain it. Say if you blog 200 posts in a single day and don't blog for 200 days altogether, your page rank might fall
3) Blogging of repetetive content - Some believed that they can pull more traffic my performing copy and paste of best articles in different websites. Again that wasn't original and they had to windup
4) They hired some SEO (Search Engine optimization) experts who helped them do some tweaking in post title, link building etc. They missed to use appropriate keywords while creating posts on a daily basis.
So, always create a sell optimized content rich post. This is automatically lead to good SEO (Search Engine Optimization)