Make sure you get your next open house information on Zillow, it is free and easy to do. The information will show up on the site a week before the event, and then automatically come down when it is over. Here is a short video that walks you thru the process:
And it works! Here is a quick story from a Realtor I met at the annual NAR convention last year. She entered the open house info on Zillow, canceled the open house but forgot to take the info off Zillow. 12 people showed up, she got a buyer and actually double sided it. The mix up turned out to be a good thing!