Realtor marketing has always been a competitive business. One of the problems that ha happened over the last few years is that people have tried linking their websites to anyone that would like to trade links. There is no problem with that as long as you know what you are getting into. Often you will go to a site and is looks like a buffet of links all asking you to go to another site instead of the site focusing on keeping customers and focusing instead on the great content that the site MUST offer.
Matt Cutts who is one of the search engine experts at Google stated earlier this week that Google is cracking down on links to unrelated sites. Examples he showed was real estate sites that had links to online pharmacies and other things that had nothing to do with what the site was about. Remember that if someone finds your content great when they will ink to you and no matter who links to you it is a good link. Other times you are trading links with other sites and in this case a link that appears on your site should be a link to something related. You can trade links with the following and have a good reason to have those links on your pages:
Realtors from out of town
In closing I must say that your Realtor Marketing must have a focus of getting links to your site and the trade off is that links sometimes have to be added to your site to do this. If you have more incoming links to your site then any of the other Realtors in your market AND your content is fully real estate related you will rank higher than anyone else in the search engines. Now go out and get those links.