Last week I did a shoot for some home sellers on a semi-rural property in the mid- Willamette Valley and I made them a custom google map that shows the property lines of their property. This can be a huge help when marketing properties where the property lines are not obvious like they are on most suburban lots.
There are some locations where if you click on the Map button in the upper right of the Google Maps and toggle the map mode to non-satellite the property boundaries will actually show on the google map (this address is one of those locations - Google appears to have integrated the local county tax record maps in to Google Maps) but this is not universally true. For non-technical agents or home sellers just having a photo that shows the property with boundary lines is very useful for marketing. Of course the agent/home seller takes the responsibility for identifying where the property boundaries are. In some areas lot lines and room dimensions are an issue with agents because they are afraid of being sued over possible errors.
For years I used to do this same thing by just doing a screen capture and drawing on the satellite map in Photoshop but stopped doing it because that violates the terms of service of Google Maps. About 5 years ago Google added the My Places features that allow you to create your own custom illustration layers over google maps. Here's a tutorial on how to use My Places.