You can highlight your own listings on the Search Results page. Use the filter in the left-hand column under "Preferences" to accomplish this. Check the box “Highlight My Listings” and press the blue "Apply" button. In the Map View and the List View of Search Results page, you will then see your listings highlighted in the area you searched on the map and in the list. Your listings are designated with a house icon and a circle.
You can remove the highlighting by deselecting the "Highlight My Listings" checkbox on the Search Results page and then pressing the blue "Apply" button.
In addition, any of your listings that surface in a homepage search of your home area are automatically highlighted with an encircled house icon.