Challenges brands face with the growth of retail media networks include:

• Closed Ecosystems: The lack of set standards across measurement and ad formats in retail media's growth has resulted in more closed ecosystems, posing difficulties for brands.
• Walled Gardens: The increasing number of walled gardens in the media environment is a significant challenge, as each retail media network operates independently, making it harder for brands to manage and measure their advertising efforts effectively.
• Measurement Standardization: The absence of standardized measurement methods across different retail media networks complicates the process of streamlining and measuring campaign effectiveness.

Campbell's Soup Co. measures the success of media buys by:

• Evaluating Campaign Performance: They look at their media buys week over week to assess how campaigns are performing.
• Optimization: They focus on what's working and optimize towards those strategies to drive week-over-week improvement in performance.
• Negotiation and Adjustment: The approach involves negotiating the deal, reviewing performance, and optimizing within the buy. If something isn't working, they optimize out of it.

Google’s third-party cookie deprecation has impacted retail media networks by:

• Boosting Retail Media Networks: The deprecation is giving retail media networks a boost, not only in the number of players in the space but also in the variety of ad offerings available.
• Encouraging Expansion: As third-party cookies become less viable, retail media networks are expanding and exploring new ways to bridge the gap between brand and retail dollars.

Walmart's Vizio acquisition refers to:

• Acquisition Details: Walmart acquired Vizio back in February, which came with the potential to open up more advertising inventory.
• Impact on Retail Media: The acquisition could help bridge the gap between brand and retail dollars, a goal that retailers have been pursuing recently. It signifies a strategic move to enhance Walmart's retail media network and advertising capabilities.

Data clean rooms are:

• Definition: Secure environments where data can be shared and analyzed without compromising user privacy.
• Significance in Retail Media Networks: As the number of walled gardens increases, data clean rooms could become essential for bringing these separate entities together to create a better user experience. They represent the next step in addressing the challenges of data privacy and measurement standardization in the retail media landscape.