Hey Liz,

I had to look this one up in the docs as I couldn’t recall off the top of my head how this worked! Here’s the link for you in case there’s extra info that you find helpful:

https://www.customer.io/docs/anonymous-events/

This is the specific part that answers your question:

“An anonymous event is an event associated with a person you don’t recognize. The event bears an anonymous_id—a value representing the unknown person, like a cookie. We store these events for up to 30 days.”

Once it’s gone, it is indeed gone forever.

A bit lower down there’s some more info that I thought was worth calling out, as it’s an important thing to note in terms of how anonymous events can be used:

“While we capture anonymous events, these events don’t do anything until you associate (or merge) them with a person.”

Personally, I’d suggest a full read of the doc so that you can get the full story about how this feature works and how to best use it. It’s a really handy feature once you’re up and running with it, but it takes a little consideration in terms of how it can best align with your customer journey. 

Hope this is helpful - I had a good refresher course myself digging through to help you 

Cheers!