Online Marketing and Advertising
Channels and formats
Online marketing spans search (paid search and SEO), display, video, social ads, email, affiliate and influencer activity. Retargeting shows ads to people who already visited the site and requires a tracking tag. Ad targeting can be contextual (matching page content), demographic, behavioural (based on past actions) or lookalike (modelled on existing customers). Influencer and affiliate promotions must be clearly disclosed as advertising.
Buying media
Ad auction pricing uses standard models: CPC (cost per click), CPM (cost per thousand impressions), CPA (cost per acquisition) and CPV (cost per view). Platforms rank ads on bid and on quality or relevance signals, so a highly relevant ad can beat a higher bid. Budgets are usually set as daily or lifetime caps, with scheduling by time and device. Landing page relevance to the ad promise affects both conversion and quality score. A/B testing changes one variable at a time so the result can be attributed to that change.
Consent and traps
Email marketing requires opt-in consent, a clear sender identity and a working unsubscribe route; bought lists breach consent rules. CTR = clicks ÷ impressions × 100. CPA = spend ÷ conversions. Confusing CPM with CPC is the classic trap: CPM is charged per thousand views regardless of clicks.
Worked example
A campaign spends €400 and delivers 50,000 impressions with 500 clicks and 25 sales. CPM = €400 ÷ 50,000 × 1,000 = €8. CTR = 500 ÷ 50,000 × 100 = 1%. CPA = €400 ÷ 25 = €16. Compare that €16 with the profit per sale before declaring the campaign profitable.