Internet marketing, also referred to as online marketing, Internet advertising, eMarketing (or e-Marketing), is the marketing of products or services over the Internet. When applied to the subset of website-based advertisement placements, Internet marketing is commonly referred to as Web advertising (Webvertising) and/or Web marketing. The Internet has brought many unique benefits to marketing, one of which being lower costs for the distribution of information and media to a global audience. The interactive nature of Internet marketing, both in terms of providing instant response and eliciting response, is a unique quality of the medium.

Internet marketing ties together creative and technical aspects of the Internet, including design, development, advertising, and sales. Internet marketing methods and strategies encompass a wide range of services:

• affiliate marketing
• behavioral marketing
• cause marketing
• contextual advertising
• customer relationship management (CRM) marketing
• digital marketing
• display advertising
• e-mail marketing
• in-text advertising
• interactive advertising
• Internet news releases
• newsletter marketing
• online market research
• online reputation management (ORM)
• search engine marketing (SEM)
  • pay per click (PPC)
  • search engine optimization (SEO)
• social media marketing
  • blog marketing
  • multivariate testing or optimization
  • viral marketing
• software-based advertising

Internet marketing does not simply entail building or promoting a website, nor does it mean placing a banner ad on another website. Effective Internet marketing requires a comprehensive strategy that synergizes a given company's business model and sales goals with its website function and appearance, focusing on its target market through proper choice of advertising type, media, and design.

Internet marketing also refers to the placement of media along different stages of the customer engagement cycle through search engine marketing (SEM), search engine optimization (SEO), banner ads on specific websites, email marketing and Web 2.0 strategies. In 2008 The New York Times working with comScore published an initial estimate to quantify the user data collected by large Internet-based companies. Counting four types of interactions with company websites in addition to the hits from ads served from advertising networks, the authors found the potential for collecting upward of 2,500 pieces of data on average per user per month.