Online advertising is the practice of promoting products, services, or brands through paid placements delivered across the internet, including search engines, social media platforms, websites, apps, and streaming services. It covers a broad range of formats and buying methods, unified by the fact that the ad is delivered digitally and, in most cases, can be measured, targeted, and optimized with far more precision than traditional offline advertising formats such as print or broadcast. Online advertising is typically bought through auction-based systems, where advertisers bid for placement based on factors such as targeting criteria, budget, and ad relevance.

Common Types of Online Advertising

• Search advertising - paid listings that appear on search engine results pages, typically bought through a cost-per-click model tied to specific keywords

• Display advertising - visual ads, such as banners or image units, placed on websites and apps within a publisher's ad inventory

• Social media advertising - paid placements within social platforms, appearing in feeds, stories, or alongside organic content

• Video advertising - ads delivered before, during, or alongside video content, including pre-roll, mid-roll, and in-feed video formats

• Native advertising - paid content built to match the design and format of the platform it appears on, blending in with organic or editorial content

• Affiliate advertising - performance-based placements where a publisher or partner is paid a commission for driving a specific action, such as a sale

Core Buying Models

• Cost per click (CPC) - the advertiser pays each time a user clicks the ad

• Cost per thousand impressions (CPM) - the advertiser pays per one thousand times the ad is shown, regardless of clicks

• Cost per acquisition (CPA) - the advertiser pays only when a specific action, such as a purchase or signup, is completed

• Programmatic buying - ad inventory is purchased through automated, real-time auctions rather than direct negotiation with a publisher

Online Advertising Vs Traditional Advertising

Traditional advertising, such as print, radio, and broadcast television, generally reaches a broad audience with limited targeting precision and delayed or indirect measurement of results. Online advertising allows targeting based on specific criteria, such as demographics, interests, location, and past behavior, and it produces measurable data on impressions, clicks, and conversions in close to real time. This lets advertisers adjust budget, creative, and targeting mid-campaign, an option traditional formats generally do not offer once a placement has run.

Key Metrics in Online Advertising

• Impressions - the total number of times an ad is displayed

• Click-through rate (CTR) - the percentage of impressions that result in a click

• Conversion rate - the percentage of clicks that result in a completed desired action

• Return on ad spend (ROAS) - the revenue generated relative to the amount spent on advertising

Building an Online Advertising Strategy

• Define the campaign objective and the specific action the advertising is meant to drive

• Select channels and formats based on where the target audience spends time online

• Choose a buying model that aligns with the objective, such as CPC for traffic or CPA for direct conversions

• Set targeting parameters based on audience data rather than broad, undefined criteria

• Monitor performance metrics throughout the campaign and adjust budget or creative based on results