I am speaking about mechancs liens, abstracts of judgment, subordination agreements, reconveyances, state income tax liens, federal income tax liens, bail bonds, abstracts of support judsgments, lis pendens, etc. Knowing about these and where they are located is pretty important.
You will want to get familiar with the county recorders web site. You can look up all of this information at the county recorders office. There are other resources that you can subscribe to like http://propertyinsight.biz/. You can also contact your local title company for a referral to other paid sites that you can access. You may also want to hire an abstractor that will look up this information for you. There are several independent abstractors that will charge you per property.