SEM, or Search Engine Marketing, is a digital marketing strategy aimed at increasing visibility and driving traffic to websites through paid advertising efforts on search engines like Google, Bing, and Yahoo. Unlike SEO (Search Engine Optimization), which focuses on organic methods to improve search engine rankings, SEM involves purchasing ads that appear alongside search results or on relevant websites.

SEM campaigns typically operate on a pay-per-click (PPC) model, meaning advertisers only pay when users click on their ads. Advertisers bid on keywords relevant to their products or services, and the search engine's algorithm determines ad placement based on factors like bid amount, ad quality, and relevance to the user's search query.

SEM offers businesses a targeted approach to reach potential customers actively searching for products or services, allowing for precise audience targeting, measurable results, and the flexibility to adjust campaigns in real-time. It's a powerful tool for driving immediate traffic to websites and achieving specific marketing objectives, such as increasing sales, generating leads, or promoting brand awareness.