In most cases, the first line item (or set of line items) you should run is a "run of exchange" prospecting line item, which you'll use to discover which audiences are receptive to your ads.
Prospecting line items will have the most available inventory, since, by definition, their targeting is broad, and would need lower CPM bids. The conversion rate will likely be lower than your more targeted line items (such as ones that use behavioral targeting or remarketing), and costs should also be lower due to the low bids. Expect lower CPM and lower conversion rate.
Primary goal: Expand your reach to discover which audiences perform best for your brand.
Suggested settings for prospecting line items
- Use low CPM bids.
- Set higher frequency caps.
- Consider using an automated bid strategy with a CPC goal to automatically scale back your spending based on performance.
- Use channel targeting to exclude inventory from low quality sites.
- Exclude first-party audience lists in audience targeting to ensure your campaign only reaches new users.
- Target specific inventory sources and channels to narrow the breadth of the campaign.