On the MLS, yes it will be displayed for agents so they can contact you directly for showings. In some cases your broker may also be able to post your email address. On “public” websites, such as Realtor.com or Zillow.com, only the brokers contact information is allowed to be displayed. The reason for this is because the MLS has rules about what information is allowed to be syndicated to 3rd party websites. Neither you, nor your broker can do anything about this, and these rules are strictly enforced.