First tools available: The Ad Library + Competitor Tracking
Advertising Inventory
The total amount of ad space available for purchase on websites, apps, or other digital platforms.
Tags:ad spacepublisherssupply and demandprogrammaticad placements
Advertising inventory is the total number of ad placements available on a platform at any given time. Think of it as "shelf space" for ads.
Every time someone scrolls their Facebook feed, watches a YouTube video, or browses a website, ad slots become available. That's inventory.
Why inventory matters:
The bidding system that determines your CPM is directly tied to inventory. More inventory = lower costs. Less inventory = higher costs.
What affects inventory:
- User activity: More people online = more ad slots = more inventory
- Platform policies: Limits on ads per page affect available slots
- Time of day: Peak hours have more inventory
- Seasonality: Holidays see more users but also more advertisers competing
Example: During Black Friday, there are more users online (more inventory), but there are also 10x more advertisers competing for those slots. The demand spike outpaces supply, so CPMs skyrocket.
You can't control inventory, but you can time your campaigns. Running ads during off-peak seasons (January, July) often means lower costs because fewer advertisers are competing for the same inventory.