Michele - You hit "the" sore spot. I agree that these estimates do not provide the public a meaningful service. If I were you, I'd start by claiming your home on Trulia. It doesn't appear you have. Trulia and Zillow provide you, me and other real estate agents both services and disservices simultaneously. As agents, we certainly understand that values change daily, which is one reason why only a licensed appraiser can provide a "market value" to a home-owner along with the written disclaimer "valid for today only". Trulia and Zillow, fierce competitors, use sophisticated algorithms to discern what the computer thinks are "comps" pulled from the most recent tax records and to provide an estimate of value for the purpose of engaging their visitors, increasing traffic and charging real estate agents fees to be promoted in certain zip codes, among other services. In this effort to attract more monthly visitors and claim the #1 spot as "the largest website for buyers searching for homes", they tend to trample on one of our most valued services - providing buyers and sellers with really great CMAs. Trulia and Zillow should consider having a big, bold disclaimer in plain view immediately beside their estimate stating that any homeowner wanting to sell this home or any buyer wanting to buy this home should contact a Realtor and get a CMA, but they don't - even though they promote Realtors on the website. Both Zillow and Trulia do provide explanations on how they determine their estimates of value, disclaim their estimates as not being appraisals, and one or both of their fine prints may also 1) encourage the buyer to obtain a CMA from a Realtor; 2) get an appraisal; and 3) visit the property. I doubt if many visitors actually read this fine print, though. They also give homeowners and their agents an opportunity to contest and/or provide more details to increase the estimates. Still, there is a growing number of disgruntled real estate agents and agencies terminating their accounts on Zillow (#90 in US traffic ranking) and Trulia (#157 in US traffic ranking ) because of many issues, including the fact that some homeowners and buyers are taking these website estimates of value to heart. We know these estimates generally are too high or too low - rarely spot on. As a Broker, I have control over where my listings are fed, and could terminate the feeds to Zillow and Trulia through ListHub and also terminate my accounts on these websites in retaliation, but don't want to cut off my nose to spite my face because of the social power and prominence of these websites in the industry - they are more influential than Realtor.com. Except for the prominent display of their estimate of value, I actually like Zillow and Trulia more than Realtor.com because you get a great FREE listing with control over your contents (including the right to dispute their estimates of value), better social interaction (like this Q&A forum), and - oh yeah - those superior website rankings. Plus, Realtor.com charges you for a "Showcased" listing and they're #187 in US traffic rankings, which as a Realtor I think both are shameful. As long as Trulia and Zillow are allowed IDX feeds to the local MLS boards and comply with the terms imposed by our Boards, they will continue to grow in power and dominance. The best way for Realtors to pursue our concern of Trulia and Zillow's prominent presentation of their estimates of value is through our local MLS boards and the NAR. These websites get OUR listing information - all those great photos and descriptions that we pay for and that WE own - subject to OUR IDX feed contract. DISCLAIMER: website rankings from Alexia as of 8AM 1/26/2013.