You're correct about the out of the box validation process for emails Amanda. For any incoming email (whether it's loaded in batch or real-time), we are checking whether the pattern of the email address is correct based on a widely accepted regular expression. The outcome of that pattern validation (valid / invalid) is injected back into the data (in the validation status attribute) so you can easily identify emails that are not correctly formatted. We are also breaking the email into the domain name, domain type and username (again so you can search on a more granular basis if need be). For example, find me all those customers that have a valid email pattern from the icloud domain in California because we are planning a marketing campaign to apple users on the west coast... We are NOT however checking whether the email itself is actually a real email address or not so please bear that in mind.
I hope this helps.