Editor's note: This series is designed to help real estate professionals evaluate the large listings services as potential marketing partners. The information is provided by senior level executives with each company.

There is no question that Realtor.com is the biggest of the listings services. With more listings than its nearest competitors and an endorsement by the National Association of REALTORS®, the site has an enviable ready-made customer base.

With the most listings, the site garners the most traffic. But with the most traffic, the site commands the most in advertising fees, if you add in all the available enhancements. Is it worth it? Many agents think so, and here's why.

Realtor.com's greatest strength lies in three areas - its marquee-name partnership with the NAR; its exclusive agreements with many MLS organizations, and its research.

The name organizations require no explanation - they are recognizable by most consumers and all real estate professionals and have translated into a lot of confidence by Wall Street investors. The exclusive agreements, of course, refer to the Gold Alliance, in which MLS organizations were paid to give Realtor.com exclusive access to listings. REALTOR.com receives data feeds from 730 MLS’s, representing more than 90% of all properties available via MLS. These two factors alone would have been enough to cripple their competition but the site has one more, unheralded ace up the sleeve.

Realtor.com doesn't do anything without a reason. Realtor.com researchers, sometimes in partnership with NAR teams, and sometimes through independent researchers, have systematically studied how consumers and Realtors behave on the Internet - where they go, what activities they like to do, how they gather and process information and what calls to action they accept.

This is information that any competitor would pay dearly to have. Errol Samuelson, vice president of product development for Realtor.com. According to Errol Samuelson, director, Professional Products, "More than 3 years ago, Realtor.com was first to the game, conducting detailed analysis on what home buyers and sellers wanted on the Internet. We continue to lead the industry in actively translating this research features that connect consumers with REALTORS, with a focus to create such contact earlier in the buying / selling cycle.”

In other words, Realtors will have to pay to play for some features, but the leads will come faster via the site's planned tools than they would otherwise, according to Samuelson.

A case in point. Realtors can be found by consumers at least three ways on Realtor.com, based on which demographic they fit in - the consumer who knows which neighborhood they want, and the consumer who is just starting to look. There is the front-page "Find a Realtor" directory where consumers can search by keyword, the "Find a Neighborhood" feature, and the "Find a Home" listings search feature. The site also promises that it is looking at other ways to showcase agents besides through listings, possibly by adding keyword suggestions that are more favorable to buyer's agents and transactional agents. The directory also leads consumers to agents with designations, through which buyer's brokers and agents who are members of REBAC will benefit, as well as other niche specialists.

Governing philosophy: "To keep REALTORS and REALTOR Firms at the center of the transaction by helping them use the Internet to interact with buyers and sellers, and improve the efficiency of their businesses." Errol Samuelson, director, Professional Products

Restrictions: Listings must come from MLS associations. Agents who buy Realtor.com services must be members of the National Association of Realtors.

Active listings nationwide: 1.3 million

Number of visitors monthly: N/A, but the site quotes 2.9 million unique visitors for Homestore

Number of viewings per listing monthly: 201

Daily updates of listings: Yes

New listing email alerts: Yes

Number of leads generated for agents : N/A

Does Realtor.com sell Web sites/pages to agents?: Yes.

Other marketing programs available?: Yes

Is Broker/office marketing available?: Yes

Most expensive: Platinum I-Lead - $829

Least expensive: Free listing

Upgrades to Web site/page available?: Yes

Affiliates where my listings will also be seen: RE/MAX , GMAC, and Prudential (franchise listings only,) Go Network (Infoseek, Disney,) Wall Street Journal Interactive, Excite, AOL, Realestate.com, CompuServe, Cox Interactive and Webcrawler (all listings)

Company revenue model: professional subscriptions, advertising, e-commerce

Last word by Errol Samuelson: REALTOR.com is committed to being REALTORS’ partner in success by:

• Keeping the REALTOR at the center of the transaction
• Providing best-in-class products, services and partnerships
• Providing innovative Internet marketing and communications tools quickly, easily, and affordably

REALTOR.com is also committed to helping make one of the most important decisions of the consumer's life simpler, faster and a whole lot easier. We promise consumers:

• Ease of use - simple, intuitive, reliable services
• Widest selection of homes, updated daily
• Sensitivity to the consumer’s needs and individuality

Overview

Pros: If you want consumers to find your listings, Realtor.com is among the best places to showcase them. Your listing always stays on Realtor.com, even when the site shares its database with other real estate companies. There are also three ways for consumers to search for agents, which is two more ways than most sites offer.

Cons: There has been some question that in its zealousness to produce lead generation tools for agents (as well as quick revenues to reduce Homestore's burn rate) that Realtor.com has a divided loyalty between keeping its promises to Realtors and providing leads to its site partners and subsidiaries, and that some leads may lead consumers away from paying agents. In two cases this year where Realtor.com has received complaints about this, one regarding HomeFair leads, and the other regarding the Local Relocation Specialist feature, it has responded promptly with an apology, a site modification, a statement, or all three.