Look closer at the online listings.
Plenty of sites—like realtor.com®—are available to help them search for properties. Many of these sites also track the property's listing history. Buyers will be able to see how much it sold for in the past compared to its previous asking prices and how long it has lingered on the market. These sites also provide snapshots of year-over-year changes in property taxes. Streeteasy allows visitors to search apartment buildings to find out what other units are renting for in the building.
Google the address to see what turns up. Remember to check the news tab, too.
Check for any permit violations.
Many local governments' building departments offer an online database of building permits filed for renovations or changes to buildings. It'll show which permits have been approved or issued. The building department also tracks violations against any properties. Sites like AddressReport may also be able to turn up such information. Plug in the address and the site reveals construction projects and any violations that have been issued against the property or complaints reported.
Neighbors can be a wealth of information, and many are talking online. Sites like NextDoor is a free forum for neighborhoods to talk about local events, real estate, crime, and more. Neighborhood groups are also increasingly popping up on Facebook. NeighborhoodScout provides a full report of the local real estate, demographics, school, crime, and home value trends of the area.
Apartment renters, particularly, may want to check out this registry. The Bedbug Registry is a crowdsourced database that provides reports of buildings that might be have bedbug infestations. The registry also lists places nearby that have had infestations.
New websites are popping up that review landlords, such as Rate My Landlord, Review My Landlord and Whose Your Landlord. A building address will reveal any reviews posted from tenants.
Get more tips on useful sources at Curbed.com.