Seattle-based ShackPrices.com, which falls into the same bucket as Redfin, Windermere and Zillow, added a new twist to its Web site today.

And, as Galen Ward, the co-founder points out on the company's blog, it corresponds nicely with a few trends -- going green, the high price of gas and road construction.

ShackPrices.com now lets home buyers search for houses along mass transit lines in King County free.

If you go to the site, you can add the option by clicking on the pull down menu to click on near transit. With the box added, you can plug in a certain bus line.

"By letting home buyers search for properties near current and future transit stops, we are giving the public a valuable tool to find homes that fit an environmentally friendly lifestyle," Ward said.