Hi @patty jo, welcome to the community!

So the most common reason you find Profiles that are not in Lists (or Segments) is because Klaviyo syncs all “Customers” from Shopify to Klaviyo.  

Shopify refers to all accounts (emails) as “Customers” - and that includes people who registered an account, abandoned a Checkout, submitted an email through a Shopify Template/Themed Form, or through any of the Shopify Apps you may have to adds “Customers” to Shopify. 

Also note, when you setup the Klaviyo integration with Shopify, you can also designate a List for all marketing consented emails into your preferred Klaviyo List.  If you didn’t specify a List, then those users will also be in Klaviyo without being in a List.

Finally, if you are using any other third party tools that integrate with Klaviyo, they could also be doing the same via the Klaviyo API.  Some 3rd party tools will add Profiles (not to any specific Lists), and some will Subscribe users to List.  Adding a Profile to Klaviyo is not necessarily the same as Subscribing to a List - so there could be some scenarios where Apps or Tools can add emails to Klaviyo (but not subscribed to a List).

Also note, because some people who are in Klaviyo, may not necessarily have consented to Marketing, be careful on who you include in your marketing Campaigns and Flows.  You may want to refer to this Klaviyo documentation on that here:

• Understanding explicit vs. implicit consent

Other resources that might be helpful:

• Getting started with Shopify

Hope that helps!

Joseph Hsieh // retentioncommerce.com // twitter: @retenion  

Thank you for explaining! This is very helpful. I will have to try implementing some of the strategies you suggest here.