SEO consists of two major parts: on-site and off-site (also called 
on-page or off-page) optimization. Just focussing on one of them means 
neglecting the opportunities that the other one opens up. It is fatal to
 think being perfect with on-site leaves room for neglect in the 
off-site optimization. This is sooo not the case.
A Definition
On-site and off-site optimization are a team. And there is a reason why people say "Never change a winning team".
On-site
 optimazitaion refers to all SEO done directly on the website that is to
 be optimized. This includes adjustments in the HTML-Code as well as in 
the editorial content. Because I don't consider myself an expert in 
technical SEO, I will focus on editorial content as well as some HTML 
tactics to better your on-site optimization.
Off-page optimization
 is the opposite to the on-page optimization, as the wording indicates 
already. But let me break it down: Off-(the)-site optimization refers to
 all measures undertaken outside the own website. Often it is 
misunderstood as pure link building. Though link building is an integral
 part in SEO, it is not the main ingredient in the optimization mix.
Off-site SEO is a mix
I
 am referring to off-page optimization as a mix, because there is more 
to it than links. If you have all the links in the world, but fail to 
master all the other implications in off-site SEO a lot of potential is 
thereby neglected. There is more to it than just (spammy) links in 
directories and social bookmark platforms. Even building a content 
network is not enough. While many agencies still operate this way, 
off-site SEO has gone further than just links from blogs.
But what
 ARE the ingredients in that mix? Other than links there is one major 
area often referred to as social signals. Social signals simply means 
what is the response in social networks towards your website, your 
content, a subpage or a posting. The more people talk about you in their
 social media feeds, the better it is for your website. Good social signals or a large quantity of them might not automatically lead to a high ranking, but it definitely adds some spice to the mix.
Ultimately,
 social signals are also links. Because talking about something in 
"social media terms" means sharing, commenting, posting and liking. 
Ultimately, those social signals create links as well and thereby add to the link mix of a site.
 
 
