SEO and content are definitely related because the search engines rank your website or individual pages according to the content they contain. Your website is known to the search engines, and also to the human visitors, by the worth of its content.
Does merely having content help you in SEO?
It depends on your competition. It’s not just any content that helps you in SEO. Having hundreds of pages and blog posts on kite flying is not going to help you appear higher for model planes related searches. The content on your website must be relevant to the primary theme of your website. What message are you trying to convey through your website and does that message address the query being used by the search engine user? You have to convince the search engine crawlers that you have got the information their users are looking for.
How can one improve SEO through content?
Generate content that is relevant, useful, and exactly talks about the topic under discussion. Take for instance, the title of this webpage; it asks “Are SEO and content related?” If somebody searches for this question and if the search engine algorithms think that this blog post contains the most appropriate answer to this question they are going to rank this blog post higher compared to other pages and blog posts. How do we do that?
Obviously the question must appear on this page at least once, prominently, in this case it appears in the title of the blog post. It is also repeated, contextually, within the blog post, this means this particular expression appears on this blog post. It doesn’t have to be repeated needlessly; use it exactly where it needs to be used.
You can also use the expression within the bold typeface (preferably just once, don’t repeated wherever your expression appears), as anchor text, in bullets, and in headings and subheadings. The basic idea is to highlight the expression and convince the search engine algorithms that this particular expression is central to what you are trying to discuss on the page.
Another way how your content can help you in SEO is creating dedicated pages for individual expressions. Again, take the question in the title of this blog post. The title asks the question and the body elaborates upon it. I’m not sure whether it is going to happen or not (with the search engines you can never be too sure) but this blog post stands a great chance of appearing higher on various search engines.