We had some questions about preparing for the next change in SEO rules from search engines like Google after the "Google's New Rules" post. However Google changes the rules, the free indexing of your site will always be based on your creation and dissemination of good content. Search engines will always try to get rid of spammers (who are evil) and ruin the authenticity of search engines. Thus, search engines will always fight and find ways to excommunicate with dodgy sites. It makes sense: the search engine's legitimacy is based on their ability to give valuable recommendations to their users. So crappy content will always be penalised.
What are your content marketing rules?
Have updated content: currency is really important online. Updated content trumps outdated content.
Have relevant content: if your headline promises one topic, make sure your keywords and paragraphs deliver.
Have valuable content: organise your content around great stuff your ideal customer wants to read.