Imagine that you are one of the four out of five homebuyers fishing among listings online. An email alert arrives in your inbox that tells you that one of the homes you like has just had a price reduction.

Reel it in, because you've just made the catch of the day.

That's why Realtor.com is campaigning to get each of 900 MLS organizations to make listings more current. The company is making a tedious door-to-door request of MLS executives to allow the aggregator to update listing data every 15 minutes.

To date, one-third of Realtor.com's listings are refreshed four times an hour. How soon the rest of the listings update is a matter of politics and money.

The NAR has had the RETS data-sharing standard in place for years, but not every MLS uses it. The ones that use it are more able to refresh listings more often. Currently, most listings are updated for changes only once a day or less, and some as infrequently as once every two weeks, mostly due to outdated software or minimal staffing.

It's more trouble to update listings this frequently, admits Realtor.com, but the goal is to keep a sharp edge for Realtors.

Explains Errol Samuelson, president of Realtor.com, "On average about 13,600 homes are sold in America every day and roughly the same number go up for sale on the nation’s 900 multiple listing services. Tens of thousands more listings have price changes or updated information that could change the property’s appeal to prospective buyers."

As real estate web sites become increasingly sophisticated with search and analysis tools, providing fresh data is more important than ever.

To make its aggregated listings stand out from competitors that publish homes for sale from newspapers, magazines, FSBOs and other real estate sites, Realtor.com is going to start putting a time stamp on all listings that show exactly when they were last updated.

This is smart thinking for Realtor.com because studies show (eVOC August 2007) that despite Realtor.com's status as number one home search for buyers, only six percent of home buyers use only one home shopping site. Twenty-eight percent visit three sites, and a whopping 21 percent visit seven or more.