Search Engine Optimisation (SEO) has always been in the process of endless change and development. When SEO has just begun, it was all about altering back-end code, a shady practice of keyword stuffing and spamming links until your ranking started to be positively well for the keywords you wanted. In short, search engines sucked. A lot.
But in September 1998, the world of online marketing and SEO has appeared to dramatically change overnight when Google was launched and stepped in into the game.
Honestly, Google did a great job of understanding ranking factors that could showcase great content, user intentions behind searches, and how to focus on beating away spammers. That catapulted Google to the number 1 search engine used but ever since then, it has been an unending race to be at the top rank for commercial keywords. It has been extremely difficult as of late.