The article Show off home to the public and watch it sell [LA Times]  discusses the open house as a marketing tool.
Some sellers question the value of opening their home to the public. A common complaint about open houses is that they attract mostly neighbors who are looking for decorating ideas or who want to keep up on property values in the neighborhood.
Although it’s true that open houses attract neighbors, this is not harmful to the marketing of your home. In fact, it can help. Neighbors often know people who are interested in moving into the community. And a neighbor who casually walks through your home during an open house — with no particular agenda — could turn out to be the ultimate buyer.
Other real estate blogs like Property Grunt  occasionally provide feedback from the trenches of open houses.
Admittedly, I had been of the opinion that open houses are used to sell a broker’s other listings, but now I am not so sure. I have received a lot of feedback from brokers I know well who assure me that they have been an effective marketing tool for the property being shown.
In a slower-paced market, I suspect open houses will be more important than ever in exposing a property to the market. Going forward, I think there will be a tendancy to over-expose a property to the point that it becomes perceived as an over-priced listing. Brokers will get a lot of pressure from their sellers to move a property quick, thus having open-houses more frequently.
But alas, the laws of supply and demand apply here too. Too many open-houses will likely reduce their effectiveness as a marketing tool and open the property to more negative perceptions about being over-priced.
Exposure is one thing. Over-exposure, even in a weaker market, is something else.