What is the purpose of your question?
Are you asking is identity security better on Facebook than Trulia?
Is your concern identity theft?
Or are you asking about reliable data regarding real estate on Facebook and Trulia?
The reality is, if you are on the internet and use anything containing your real name and/or address....you are at risk. Internet security is an illusion. Fortunately, with a gazillion billion folks on the net, it is really hard to spot David Cooper. But, what's the choice we have? sigh.