This would break a lot of standing marketing/long-term lead nurturing efforts. It sort of forces marketers to engage with users they have in their actual databa

This would break a lot of standing marketing/long-term lead nurturing efforts. It sort of forces marketers to engage with users they have in their actual database or do everything in 30 days. Some sales cycles are a lot longer than 30 days. In publishing its pretty relevant to know if long term visitors stop coming back in the aggregate. There are lots of legitimate business purposes for anonymous longer term tracking. Counterpoint: if a data collector stores the ad id or derivative of it with anonymous activity then later links it to a user account with PII that could break a lot of basic assumptions the user may have about their privacy. That would be difficult to prevent from happening with a technical solution.