I'm using match/deduplication rules to match to accounts by website domain, and also to other contacts by email address domain. We just use the "website" field from the account for the match field on the account side, and the email address domain field on the contact side.
Here is a screenshot of the rule that matches to other contacts based on the email address domain - it also checks the city, which helps prevent false matches:
For the deduplication handler for this one, just use "update a field with field values from the matched records" and update the "SFDC Account ID" field in one contact with the value of that field from the other contact - that associates the new contact with the same account the other contact was associated with.
Does that answer your question?