I asked Jan to enter the discussion as she is a provider to these sites. So see her response to you below. I will add:
Your statement: "It should be pointed out that Realtor.com, which is by far the most popular site, is a direct feed type of site, but typically only if your agent's broker allows that..."
Before the policy change, the only way a listing did not show in Realtor.com was if the broker checked "no". So your statement about the borker "allows that" is no longer the case. NWMLS does not do it even if the Broker "allows it". The broker must employ a separate service, like Jan's. Consequently, the method of an offices listings being on Trulia or Zillow or Realtor.com are pretty much the same, without any automatic or preferential treament via NWMLS for any of them, or similar sites.
The BIGGER issue is that the manner that this feed is implemented is via a NWMLS download agreement, and each office or broker is drastically limited in the number NWMLS will provide. It used to be two, but when NWMLS stopped the feed to Realtor.com, Jan and others managed to get an additional ONE approved, making it three. Still not enough to feed to multiple sources, since the broker uses one for his one site. This is why agents are not free to have their own site with just anyone, as agents don't get to have a "download" agreement and all agents are subject to the limited feed access of the broker.
Big issue...It would seem to me that a broker doesn't have enough feeds to do all of them...so they have to choose one vs. another at present, given they only have 3 feeds and two are usually already being used by the broker for other office purposes.
Originally Trulia was a "scraper" site and pulled listings from anywhere on the web without approval by the owner, the mls or the agent. At that time you couldn't individually list a home on Trulia. They changed that aspect, but I don't know if they eliminated "scraping", and am pretty sure they have not. So a listing may show because the listing appears on an agent's site and Trulia "scraped it", even though no one approved it to be there.
You may remember that Trulia elected to OPEN in NYC (as I recall) an area that has no MLS, making a scraper site quite invaluable to potential buyers.
Your assertion that Realtor.com is the "most popular" may or may not be true in any given area from time to time. In some areas it is Zillow...in others it is Trulia in others it is a local brokerage site, as to the potential buyers of homes in that location.
Trulia is not a "Brokerage Site" nor is Zillow. Your listing "can" show on those two sites, but it is not automatic as a result of putting your home "in the mls". Some Brokerages have a direct feed outside of the norm, but that has to be instituted by the Brokerage, vs the mls system. Your agent can also cause your home to be in Craigslist and many other sites, as an individual effort.
The disadvantage is that without a direct feed from the mls, there is not an auto update when the price changes or the property is sold. So if you manually "put" it in a lot of places, make sure you know where you did that so you can do the manually updates.
Any Brokerage site showing property via a direct feed from the mls will have automatic updates from one source...others...not.
Trulia is an aggregator of listing data. The NWMLS allows each broker two download agreements, so many brokers do not allow their listing data to download to Trulia. Data aggregators only do their downloads a couple of times per week, because aggregation is a newer technology.
The real question is whether or not your listing is exposed to ready, willing and able buyers. Through the NWMLS, any agent who is a member can see your listing the minute it is submitted. The ready, willing, and able buyers, at least 87% of them, based on surveys, are working with agents.
Some agents enter their listings by hand on Trulia to try to capture leads.
Every broker in the Northwest mls has the right to show the listings on their websites. Personally, I am with a national company that provides agent and office websites, so on my own personal website, you can search all listings in the mls.
This system of private aggregators trying to get a piece of the actions, plus brokers marketing through the internet has created ready exposure of your listing. I'm wondering if your wondering why your listing hasn't sold. The true answer on that is how well your property is positioned competitively based on its value.
Given the new addition to the Code of Ethics at the mid-year conference regarding comments on social media platforms and blogs, I didn't want to get into broker specifics without naming several, making sure to dispay as big, small, big, small :) The ink isn't dry yet on the new potential infractions...so I'm doing a bit of CYA and suggest you do that as well for the time being.
One provider with one download to send your listings to multiple places is going to be the end result, and is somewhat available as we speak. That solves both issues. Similar to using Postlets to feed out to multiple sources.
In my neck of the woods, people have heard of more things, including Redfin, than down in Tacoma...or so I hear from agents down that way. Real Estate is getting VERY "local".
BTW, that 3 feed thing sounds vaguely familiar. I really wish the NWMLS would just open it up so that the agent could select which sites they want their listings to go to. Check boxes.
Realtor.com does not have a preferred treatment vs. Zillow and Trulia per your previous comment, and any or all can be accessed through broker arranged feeds, but it is not automatic as it is with a Broker IDX site, per my original response.
So those telling Kirby "just wait a couple of days" are only correct if the agent or the agent's broker made specific separate arrangements.
NWMLS changed that policy (direct feed to Realtor.com) back in 2007 or 2006. They could not justify the rationale to do so for Realtor.com and not Zillow and Trulia and the ever increasing number of new non-member sites.. The process to feed listings to Realtor.com became the same as for Trulia and Zllow.
I do not think they have reversed that policy. Jan Chapman of Locial Dog spearheaded a petition against that policy and provided a nominal cost feed solution for small companies. I'll check with her to see if that policy was reversed.
Appearing in the mls does not automatically guarantee that the home will show on a non-brokerage site such as Trulia. The home will show on all mls "member" sites, and Trulia is not a member of the mls.
Other sites, such as Trulia, Zillow, etc., require some third party feed. Ones your agent might use include Postlets.com and virtualtours.com. I also use the "Keller Williams Listing Service" which feeds to such sites. Those need to be manually updated each time there's a change in price or status to the listing.
It will sometimes take 2-3 days for these sites to all update to Trulia.