Updating what your contact wants to hear about can be managed by them however you can also effect what they hear about.
Essentially there are 2 options to define what a contact will hear about...
1. What marketing lists do they belong to
You can attach a contact to any number of marketing lists by editing the contact, selecting the lists to attach them to and press save.
2. Their marketing preferences
Set what top-level information they want to hear about: Latest News and Property Alerts.
If they care about property alerts you can jump in and update their preferences to set what properties they care about.