Perhaps there was some personal property left behind or someone lived in the house for a while after the foreclosure and that caused the bank to check a box in their database.  

It is Yearly(Income - Expense) / Purchase Price.1) Income - In the old days, you will need to go ask some agents and/or go to MLS (Multiple Listing Service, the "database" for agents to look for rental listings) as to how much the rent your neighborhood is.  

It is robust, can use a real database back end and, at the time, had better multi-currency and international support than QuickBooks or Simply Accounting.  

This probably is going way overboard, but when my wife and I moved and rented out our former residence, I created a wiki database (similar to Wikipedia) for the house.

We have used the standalone keypads in the past, but typically use the Zwave enabled locks to allow them to be remotely managed.

The company created a logo, designed the website and created a simple database.

It also comes with Backoffice Pro which is a database management software to track leads and upload your deals.

Padlister has recently gotten so powerful, I'm using it as my database for vacancies.I can set up open houses and get prospect contact information without ever answering a phone call.One small annoyance right now is that CL has blocked padmapper/padlister (pm/pl) links in CL ads.

Libel no... but I believe they can come after you for harassment.Someone once mentioned the idea of creating some sort of deadbeats database for landlords, etc... and a similar argument was brought up.

I have worked with Heartland MLS (Kansas City area) in the past and one way I've found to help get me closer to what I want is to create data exports within MLS (to csv format) and import them into a database.