Yep, and with all the 3rd party add-ons, you can make it do some very interesting things.Notes - sign PDF Contracts on the iPad, Dropbox - move PDF Contracts and files between all my computers and devices, MightyMeeting - to present and share listing or selling presentations, Wunderlist - ToDo list between devices, Total - nice way to capture property data like measurements etc.
Dropbox to move files to iPad, MightyMeeting to do presentations on (also shares presentation on other computers), Notes to physically sign contracts on iPad using a stylus, Zillow or Trulia to show buyers or sellers what is around the property (comparisons), Foreclosures to see all foreclosed properties around a house, AroundMe to see what is near a property (stores, shops, etc), Skype for obvious reasons, Hootsuite to manage SM, DocScan HD in case I need to scan (take pic) of documents to send, ArcGIS to look at GIS maps.
Kelley, what is your objective in building the app? You your use, clients use?
If I did, it would be only for complimentary services like mortgage broker, insurance, etc. And even then you may have to disclose you receive an advertising fee, if your client uses them.