Search engine marketing (SEM) is an important way for brands to reach online audiences. SEM includes both organic search (SEO) and paid search (SEM). Paid search advertising is bought through auctions on search engines and advertisers only pay when their ad is clicked. Key factors that determine ad positioning include bids, quality scores, and match types. Optimizing bids, ad copy, extensions, and keywords can improve performance. While Google dominates the search market, advertisers can access other search engines' networks. SEM and SEO work together synergistically. Current trends show increasing digital ad budgets overall and a shift to mobile search driving the consumer journey.