Perhaps the most valuable data to use in Singulate is precisely the data that other ESPs struggle with: unstructured text from open form fields.
These are in contact sales forms, event registration forms, lead magnet forms, and any other email capture on your website.
Any fields that ask “What can we help you with?” “What are you looking to solve?” “Who are you looking to meet?”
These are extremely powerful for personalization.
Other examples:
Try to import only data attributes that are relevant or interesting to use to build segments or personalize content with!