Real estate works surprisingly differently in different countries. In France real estate agencies are used for pretty much every deal (afaik), in Germany there's quite a lot of local listings in papers or dedicated websites that cut out the realtor (standard contracts are freely available, the process is pretty standardized). I don't know how it works in the US but in Germany eBay classifieds for rental are becoming more and more popular so that may be a direct competitor down the line.