In the old days in Real Estate, there were local organizations that realtors congregated to to share their listings. It was a necessity. The Internet was non-existent, and the first computer based systems to share listings were proprietary, and required users to sign up and pay to become members. Thus, the advent of MLS. Many Realtors, especially in rural areas such as where my folks are, still believe that being a member of their local MLS system to get exposure for your listings is a necessity.
I believe that will gradually change, and here are some reasons why:
Cost - MLS Systems charge a significant amount of money, while there are more and more places on the Internet where you can post listings for free - I've mentioned that before and I'll be back later with another articel on my favorite hit list.
Monopoly - May of these MLS systems operate form a business model of "No competition". For example, if you want to deal Real Estate in Hillsdale Michigan youhave to be part of the SWMRIC MLS. Period. Which brings me to my next sticking point. Service. This tends to cause these systems to be less driven to provide better service and site functionality. Some MLS Systems won't allow access to the general public at all, and do things like prevent you from downloading photos.
Discontinuity - With My folks Real Estate Office, they are in a geographic area that requires them to become members of 3 separate MLS systems for 3 counties. Two of those systems are from the same company, so they effectively have to pay twice to use the same software.
Data Feeds - These systems allow members to receive and post all listings on their own personal sites, but I've looked at the format that some of the data currently comes in and its pretty rough. Zipped excel files. XML is they way they need to start going with this stuff to stay competitive. Also, when you sign up, current rules allow other realtors (at least in Michigan) to post your listings next to a nice big picture of them, only crediting that actual listing in the fine print. These are typically public Internet websites and many end consumers don't realize that the real listing agent is way down below in the fine print. Now why would I want my listings in a system like that?
Lack of Search Engine access - Most MLS Systems themselves can't be crawled by search engines, so you won't find listings from MLS systems by looking on Google.
In short, I believe in time - and it may take a while - more and more realtors are going to start seeing and believing in other Internet advertising strategies, and unless local MLS systems get more effective and competitive, they'll either go by the wayside, or get swallowed by the MLS Systems that do a better job of competing.
For an example of how the Internet is slowly begining to fundamentally change the Real Estate Market, see this article by Nick Karris at Gomez.com