Ad Rank is a crucial factor in PPC as it determines the position of an ad on the Search Engine Results Page (SERP). It is calculated based on the bid amount and the Quality Score, which assesses the relevance and quality of the ad and the landing page. High Ad Rank ensures better visibility and potentially lower costs per click.

Cost Per Click (CPC) is the amount an advertiser pays for each click on their ad. It can vary based on the competitiveness of the keywords and the Ad Rank. Bid Adjustment allows advertisers to increase or decrease their bids based on factors like device type, location, or time of day, optimizing their spending.

Click-Through Rate (CTR) measures the percentage of people who click on an ad after seeing it. A high CTR indicates that the ad is relevant and compelling to the audience. Conversion Rate, on the other hand, measures the percentage of visitors who complete a desired action (e.g., making a purchase) after clicking the ad. Both metrics are vital for assessing the effectiveness of a PPC campaign.

Negative Keywords are terms that advertisers exclude from their PPC campaigns to prevent their ads from showing up in irrelevant searches. This helps in focusing the ad spend on more relevant queries. Impression Share is the percentage of times an ad is shown out of the total available impressions, indicating the ad's reach and visibility.

PPC is a key component of Search Engine Marketing (SEM), which encompasses all paid search activities to increase visibility on search engines. Affiliate Marketing involves partners promoting a business's products or services in exchange for a commission on sales generated through their referral. While distinct, both can benefit from PPC strategies to drive traffic and conversions.