When you set up a customer as a Contact in Matrix, not only does it create a Portal for them (which is where they are brought when they open up one of your Matrix emails) but it also allows them to perform their own searches against the MLS listings database. The number of fields accessible to them on a Portal search screen is limited (and not customizable), but it does give them the flexibility to search for listings using different criteria than that which you used in their Auto Email search.
When a Contact is in their Matrix Portal, they can click on the Start a New Search button to open up a search screen and enter their own search criteria:
They will not have the same fields on the Portal Search screen that MLS members have when logged into Matrix, nor can they customize the search or add additional fields to it. But it does enable them to run their own searches, in case they may be interested in looking for properties that do not match the Auto Email saved search you set up for them.
Note: only the previous 2 years of Closed listings are available in Portal searches.
After entering their criteria and clicking Apply, the Portal will display any matches. They can then save their search so they can re-run it at a later date. These saved searches are accessible by clicking My Searches.
As their agent, you can see if they have created any saved Portal searches by going to My Matrix> Contacts and looking for the Portal Searches section. It will show you the exact criteria they used in their search: