I am with Diane on this one . . . online estimates of true house values tend to be grossly inaccurate (due to their lack of hands on knowledge of the area and property specifics) and this is an ongoing issue for us Realtors as buyers agents as for some odd strange reason online estimates seem to take precedence over an expertise of the area (heck what do we Realtos know, we just visit properties and apply our knowledge on a daily basis). Unfortunately this is part and parcel due to the infancy stage of most online portals that report house values.
In defeinse of Trulia v. Zillow, Trulia merely reports the last sold price whereas Zillow pretends to report true value, which is most circumstances is not doing justice to real value.
I share in your frustation.
Francesca Patrizio, Realtor, ePro