In some contexts, the term SEM is used exclusively to mean pay per click advertising, particularly in the commercial advertising and marketing communities which have a vested interest in this narrow definition. Such usage excludes the wider search marketing community that is engaged in other forms of SEM such as search engine optimization and search retargeting.
The kind of content you create depends on your audience's needs at different stages in the buyer's journey. You should start by creating buyer personas (use these free templates, or try makemypersona.com) to identify what your audience's goals and challenges are in relation to your business. On a basic level, your online content should aim to help them meet these goals, and overcome their challenges.
A content marketer, for example, can create a series of blog posts that serve to generate leads from a new ebook the business recently created. The company's social media marketer might then help promote these blog posts through paid and organic posts on the business's social media accounts. Perhaps the email marketer creates an email campaign to send those who download the ebook more information on the company. We'll talk more about these specific digital marketers in a minute.