While the real estate websites offer contact forms to send e-mails, many people hate dealing with e-mails. Landlords and even "professional" real estate agents often ignore e-mails. Sometimes it is because of the sheer volume they get, but I suspect often it is just that they never really adapted to the medium.
Many (most?) ads include a phone number. And I have had far better results by calling than by sending an e-mail. You should of course be one of the first people to call...