When you select 'Export Your Contacts', a .csv file is sent to your email containing the following of all your contacts:
company_name
company_address
company_phone_number
company_website
company_fax
company_description
company_tags
company_notes
company_external_id
first_name
last_name
title
secondary_email
mobile_phone
home_phone
other_phone
role
address_label
address_line_one
address_line_two
address_city
address_state
address_country
address_country_name_override
external_id
tags
notes