Hi, you're in luck! I'm actually creating a website similar to the website you mentioned but with more features and more user friendly.
Anyways, as far as I know. The "OHW" website (short) does not scrap. And if I were you I wouldn't either (unless you want a lawsuit on your hands) I believe they signed contracts with the individual agents and therefore have particular access to their listings only. (brought to you by treb) For more details contact me @ info@weeklyopenhouse.ca I'd be more than happy to share with you what I know.
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we're in the process of launching our project
www.WeeklyOpenHouse.ca. Should be up and running by next week. I would love to get some feedback/comments. If interested, I would love to show a demo version. Contact me for website address. Thanks!