The ad auction process takes place every single time someone enters a search query into Google. To be entered into the ad auction, advertisers identify keywords they want to bid on, and state how much they are willing to spend (per click) to have their ads appear alongside results relating to those keywords. If Google determines that the keywords you have bid on are contained within a user’s search query, your ads are entered into the ad auction.
Not every single ad will appear on every single search. This is because the ad auction takes a variety of factors into account when determining the placement of ads on the SERP, and because not every keyword has sufficient commercial intent to justify displaying ads next to results. However, the two main factors that Google evaluates as part of the ad auction process are your maximum bid and the Quality Score of your ads.
Another ethical controversy associated with search marketing has been the issue of trademark infringement. The debate as to whether third parties should have the right to bid on their competitors' brand names has been underway for years. In 2009 Google changed their policy, which formerly prohibited these tactics, allowing 3rd parties to bid on branded terms as long as their landing page in fact provides information on the trademarked term. Though the policy has been changed this continues to be a source of heated debate.
Digital marketing is defined by the use of numerous digital tactics and channels to connect with customers where they spend much of their time: online. From the website itself to a business's online branding assets -- digital advertising, email marketing, online brochures, and beyond -- there's a spectrum of tactics that fall under the umbrella of "digital marketing."