Is a subscriber's 'Date Added' searchable?

When a subscriber joins a list, we can also add or remove them from other lists, but is it possible to set some custom field with a searchable date?

Specifically, I'm trying to find the best way to dynamically segment out users who are 2 days old (i.e., where Date Added is equal to [PAST_DAYS_2], or better yet whose Date Joined LIST is [PAST_DAYS_2]).

Being able to set a custom field on List Join would be a useful feature.