Google Ads (formerly Google AdWords) is an online advertising platform developed by Google, where advertisers bid to display brief advertisements, service offerings, product listings, or videos to web users. It can place ads both in the results of search engines like Google Search (the Google Search Network) and on non-search websites, mobile apps, and videos. Services are offered under a pay-per-click (PPC) pricing model. Google Ads is the main source of revenue for Alphabet Inc, contributing US$168.6 billion in 2020. History Google launched AdWords in 2000. Initially, Google set up and managed advertisers' campaigns. Google soon introduced the AdWords self-service portal to accommodate small businesses and those who wanted to manage their own campaigns. In 2005, Google started a campaign management service known as 'Jumpstart'. The AdWords system was initially implemented on top of the MySQL database engine. After the system had been launched, management decided to use Oracle instead but was eventually reverted to MySQL after the system became much slower. Eventually, Google developed a custom distributed Relational database management system (RDBMS) known as Google F1 specifically for the needs of the Ad business. The interface offers Spreadsheet Editing, Search Query Reports, and conversion metrics. In 2008, Google launched the Google Online Marketing Challenge, an in-class academic exercise for tertiary students. Over 8,000 students from 47 countries participated in the challenge in 2008, over 10,000 students from 58 countries took part in 2009, about 12,000 students in 2010, and almost 15,000 students from 70 countries in 2011. The challenge runs annually, roughly from January to June. In April 2013, Google announced plans to add enhanced campaigns for AdWords to aid with campaign management catered to multiple-device users. The enhanced campaigns aimed to include advanced reports about conversions. In July 2016, Google unveiled "Showcase Shopping" ads. With this format, retailers can choose to have a series of images that appear in search results related to various search queries and keywords. In October 2017, Google revised AdWords' daily budget caps, which were previously set at a maximum of 120% of preset daily budgets, to a maximum of 200%. This change was rolled out on the same day it was announced, prompting criticism from paid search professionals. However, Google later clarified that this change would affect only short-term campaigns of less than 30 days and that for campaigns running more than 30 days, overage charges would be refunded. On June 27, 2018,