Clark gets calls from landlords who are having terrible problems with tenants who don’t pay rent or trash the properties. He often sends them to landlord.com. But now there is something even more helpful for landlords and possibly hurtful for tenants. There is now a database listing questionable tenants called the “Tenant Black List.” Landlords can search the database for your name and refuse to rent you an apartment because you are on it. But there are potential red flags with this system. The UD registry, as it’s officially called, has had some mistakes. A name can appear on the list by mistake or out of spite by a former landlord, and that person may be completely in the clear. There is also no appeals process, which bothers Clark. So, some states are fighting back. Minnesota has implemented a law saying you can have your record purged from this list if it’s found that you were not at fault. Computer technology has become so affordable and sophisticated that data mining companies are able to develop customized reports for various industries. So, take action if you are blacklisted.