Google AdWords is Google's main advertising product and main source of revenue. wikipedia.org

Google Shopping, is a Google service which allows users to search for products on online shopping websites and compare prices between different vendors. wikipedia.org

Search engine marketing, (SEM), is a form of Internet marketing that seeks to promote websites by increasing their visibility in search engine result pages (SERPs) through the use of paid placement, contextual advertising, and paid inclusion. wikipedia.org

Lead generation, or lead gen is a marketing tool used, particularly in internet marketing, to generate consumer interest or inquiry into products or services of a business. wikipedia.org

Pay per click (PPC) (also called cost per click) is an Internet advertising model used to direct traffic to websites, where advertisers pay the publisher (typically a website owner) when the ad is clicked. wikipedia.org

Email marketing is directly marketing a commercial message to a group of people using electronic mail email. wikipedia.org