Search engine optimization was first mentioned as a profession in late 90s. With the appearance of search engines webmasters realized they could benefit if their website was more visible to the target audience. At first all they had to do was submit their website to a search engine directory to be indexed, relevance was being determined by the keywords in meta tags; that was proved unreliable from the search engines point of view, because webmasters could input keywords unrelated to their websites content. That caused search engine provides to come up with more complicated algorithms and on the other side the need for specialized SEO experts.
At first most if not all of SEO experts were self taught, worked in marketing field or were web developers who did SEO as a side activity. As the profession became more popular and sought after specialized courses started appearing.
There are, as in every field, pros and cons to choosing SEO as your career. The good side is that there is currently high demand for SEO experts and it is going to be on the rise in the future, SEO is a high paying job even when compared to maybe more technically demanding jobs such as web programming and web design. Another good side of SEO as a career is that you can work in a company as an employee or from home as a freelancer and still make considerable amount of money or even more. In order to do SEO professionally you should have at least some basic knowledge of HTML, the more you know about it the better, because you will at some point have a need to edit or implement some HTML code in order to get the best results. Another useful skill is knowledge regarding social media, as social media is already very important part of SEO.
The negative aspect for some people of doing SEO includes a work done to implement your conceived strategy. It is a lot of work and often very repetitive, some times you have to do the same thing for hours at a time. Therefore you have to have a lot of patience and be detail oriented. Another bad and maybe sometimes frustrating issue is that there are no clear and permanent rules, the ones that are valid today may change in a month and mean absolutely nothing and even become banned. You have to follow the trends all the time and be able to adapt to change in order to be successful in the industry.
Also the results are not immediate, you have to wait for some time in order to see if your strategies had desirable effect on the rankings. It would be helpful to have end goal in mind in order to not get discouraged easily.
Than there is black hat SEO, that includes practices and strategies that are forbidden by search engine providers or unethical, that is cheating your way to get quick results, that creates unfair competition to the people who do it by the rules, but in the long run it isn’t worth it because sooner or later websites that were positioned using those techniques get penalized and all the work goes in vein.