Additionally, there are many situations where PPC (a component of SEM) makes more sense than SEO. For example, if you are first launching a site and you want immediate visibility, it is a good idea to create a PPC campaign because it takes less time than SEO, but it would be unwise to strictly work with PPC and not even touch search engine optimization.
Another challenge is the sheer scope and scale of digital marketing. There are so many great digital marketing techniques ranging from search, social and email marketing to improve the digital experience of your website. Our article, What is digital marketing? shows how by using our RACE planning framework you can define a more manageable number of digital marketing activities which cover the full customer journey. Within each digital marketing technique, there are lots of detailed tactics that are important to success, so they need to be evaluated and prioritized, for example from dynamic content for email automation, website personalization to programmatic, retargeting and skyscraper content for organic search.