For retargeting subscribers who click on links of key items in emails, which skill set does the customer team need to possess?

The correct choice is AMPscript. This programming language is specifically designed for use within the Marketing Cloud environment, particularly to personalize email content and to manipulate data in real-time. When it comes to retargeting subscribers based on their interactions, like clicking on links within emails, AMPscript allows the customer team to dynamically tailor messaging based on subscriber behaviors. It can access and modify content based on both subscriber attributes and engagement metrics, thereby making it particularly effective for creating follow-up campaigns for subscribers who display certain behaviors, such as clicking on specific links.

In contrast, while HTML provides the structure for emails and ensures that they are visually appealing, it does not handle data manipulation or personalization. SSJS (Server-Side JavaScript) is used for server-side scripting but is generally not as straightforward for real-time personalization in the context of email campaigns as AMPscript. SQL is primarily used for querying and managing databases, which is less relevant for the dynamic personalization required in email content following subscriber actions. Therefore, AMPscript stands out as the essential skill set for the customer team when it comes to effectively retargeting subscribers based on their link activity in emails.