I live in the city of Chicago, and when we were buying a house 6 years ago, proximity to the Blue Line was something high on our list of 'needs'. Problem was, I was new to Chicago, so it wasn't easy for me to know if there was a train close to the home we were viewing. Today's home shopper can now look this data up in a cinch. And even better, WalkScore has free APIs for you to add this data right on your site.
In case you aren't familiar with WalkScore, it is a great site that will give a home a 'walkability' score, based on proximity to various establishments(restaurants, grocery, transportation, etc). A few weeks ago, they updated their algorithm to calculate the score based on actual walking paths, verses how the crow flies, which I think is a major upgrade.
Today their information is even richer with the addition of a Transit Score, or the home's proximity to public transportation. Now when I type in my home's address I also get this information:
Plus, if you click on the "commute" tab, even more information is available. Say I had to commute from my house to the NAR Building downtown everyday:
Highly encourage using the information which Walkscore.com gives away for free, by visiting this link WalkScore on Your Site. I think it is information that your visitors will really like.