I disagree with you here. Google are refining their algorithms, but there are not often major changes, and on the whole, those changes target sites which have been using dubious techniques to gain ranking. Reputable sites have nothing to worry about from these changes.
I don’t think SEO is changing frequently at all, and I certainly don’t think it’s becoming harder. On the contrary, I think it’s become easier. What really matters now is having a well-structured site with high-quality, unique content. As that’s something which you will, of course, want to create for the benefit of your site visitors, it means good SEO involves very little extra effort.
To me on-page SEO is the most important element
Go with the useful content and try to link it a little bit. Plus - use social media. Google really likes those three elements.
I’m not sure how you’re suggesting social media could be used for SEO. Most social media links are nofollow, and therefore have no effect on search engines.
Personally I think article marketing is very helpful. But you have to ensure the quality.
The content is the king after this good amount of do follow backlinks matter.
This discussion seems to have come full-circle, and the OP has never returned.
Thanks to all who contributed, but I think it’s time to close this.