As noted above, cookie-based user targeting includes targeting remarketing lists.
ITP technology significantly shrinks these remarketing list sizes, transforming remarketing users into “ghosts”. Also, ad frequency capping cannot be controlled anymore as it is impossible to identify persons that have already viewed this ad and viewing frequency.
Furthermore, standard bidding algorithms cannot recognise the conversion attribution to cookieless browser traffic. Therefore, it would be undervalued even if it is in fact highly convertible.
Google devised several possible solutions for avoiding strong negative impacts on ad campaign performance.
The first recommendation was an extensive implementation of Customer Match technology, which is currently broadly available for many Google advertising formats.
Customer match allows displaying ads to customer lists (for e.g. from CRM systems), or to similar new users. However, this feature is not available on third-party sites in the Display Network.
Instead of remarketing, other types of Google audiences (for example, In-market, Custom Intent, Similar etc.) could also minimise the negative impact of cookieless browsers. This is because they are products of contextual and environmental signals, amplified with machine-learning. And hence, can help to find the relevant audience suited to the product.