Home buyers and home sellers alike can find more innovative and useful features than ever on real estate Web sites, which are nimbly adapting to the U.S. housing slump.

For those poking around the real estate market, it might be worthwhile to check out sites like buysiderealty.com, iggyshouse.com, zillow.com and trulia.com to see just how much online home shopping has changed lately.

In the past, most real estate sites primarily offered property listing services. That's no longer the case thanks to improved online mapping services and the spread of broadband connections, which have allowed sites to take advantage of new technology.

What's more, as a means to drum up business, real estate sites have looked to expand their features to include services like alerts, heat maps showing active sales areas, video postings, home estimates and Q&A forums. Some are even offering rebates to home buyers.

Chuck Cole, for instance, recently bought a home in Oakland, California, worth almost $450,000 -- and met his realtor just once through the entire month-long process.

Cole used the multiple listing service tool on buysiderealty.com to pick the properties he wanted to visit. Later, after deciding on a house and submitting an offer, he had a realtor from buysiderealty.com handle the transaction.

For doing all the groundwork himself and bypassing a traditional realtor, Cole was rewarded with a rebate of over $8,000, or 75 percent of the buyer's commission that buysiderealty.com earned from the deal.

We liked that everything was done pretty much by e-mail and phone. When we've worked with realtors in the past it was a big pain in the neck to try to connect with people in person and to have to go to their office, said Cole.

MARKET SLUMP SPURS BOOM

If you're looking to sell your house without using a real estate agent, consider a visit to iggyshouse.com, a sister concern of buysiderealty.com.

The site lures sellers with freebies like a multiple listing service, a listing on realtor.com and posts on other sites. Home sellers once paid agents a premium for such services.

Iggyshouse.com also lets sellers and real estate agents post photographs, videos and details about the property for sale -- at no cost.

With 75 or 80 percent of sellers (also) being buyers, we know that if we give them this free service and they are self directed enough to sell on their own, there is a pretty good chance that they'd want to use (the) buyside, said Joe Fox, chief executive of iggyshouse.com and buysiderealty.com.

We're basically giving a free service to educate consumers about another service that pays them to use it and that's exactly what is happening today, said Fox.

Another Web site that has entered this increasingly crowded space is zillow.com, which launched in early 2006. It not only offers free property listings, but also gives away a home valuation service it calls Zestimate.

Pete Flint, CEO of trulia.com, says the housing market's downturn has played to the strengths of real estate Web sites.

Although it's unfortunate what's going on in the housing market, it's really the online sites that are benefiting because consumers are spending a little bit more time before they make decisions and traditional real estate brokers are rethinking the way they're marketing themselves, Flint said.

So the change in the housing market has forced a change both in consumer behavior and forced a change within marketing activity for real estate professionals and we are a perfect platform for them both, he added.

Trulia.com, which launched in 2005, has signed agreements with thousands of agencies that post all their available property listings on the site. Trulia.com, in turn, generates revenue through advertisements placed on its site.

On the site you'll find services like trulia voices, which allows you to pose questions to local residents and agents on subjects as unexpected as the location of the nearest dog park.

If you'd like to be alerted every time a property in a particular neighborhood goes on sale, trulia.com also sends you free alerts. Another feature is heat maps that help you gauge the demand and average price of properties in certain spots.

The reality is that the actual (real estate) transaction is not changing, so people are still going to go to open houses and drive around neighborhoods, but the actual process of research for the real estate transaction has radically changed, said Flint.

California