Real estate information sites such as HouseSigma and MongoHouse are already listing sold prices for Toronto houses online after a ruling last week by the Federal Court of Appeal.

That information from the Multiple Listing Service used to be kept secret by the Toronto Real Estate Board (TREB), which said only its agents had the right to share that information with their clients.

Last Friday, the Federal Court upheld a previous decision in favour of the Competition Bureau, which had argued that TREB's practice of keeping information about home sale prices and real estate agent commissions secret is anti-competitive and bad for consumers.

A normal business would sit down and ask themselves: 'Hey, what do our customers want' and then find a way to deliver on that need - Ara Mamourian, Property.ca

TREB plans to appeal that ruling to the Supreme Court of Canada and is seeking an order to stay the decision in the meantime. TREB CEO John DiMichele argues that is personal financial information that should be kept private.

Ara Mamourian welcomed the court ruling that sales data should be public. He's been sharing sold data with clients. It's 'what's right,' he says. (Spring Realty) Some real estate agents are taking a cautious approach waiting for that final appeal to work its way through the court or new rules to be issued before making sold prices widely available.

Real estate broker Ara Mamourian campaigned publicly to allow the release of sold prices and has been sharing sold prices via email with customers.

He says it's just good business to allow consumers to know the data, as they are making a huge financial decision and need as much information as possible.

"A normal business would sit down and ask themselves: 'Hey, what do our customers want' and then find a way to deliver on that 'need,'" he said in a Dec. 1 blog post, which criticized TREB for pushing back against the court ruling.

That data's not personal

He disagreed with DiMichele's statement that sold data is personal financial information that consumers do not want released.

But for now Mamourian is not adding sold data to his website, formerly Spring Realty, now owned by Property.ca.

"We're not doing anything differently other than continuing to do what's right. What's right you ask? Sharing sold data with clients who need it. We're not actively publishing sold data now but our parent company Property.ca is likely best positioned to take advantage of and publish once there's more clarity around the new rules," he said in an email to CBC News.

Meanwhile, MongoHouse, HouseSigma and Sold.Watch have rolled out websites with the information and consumers have been flocking to them. HouseSigma also has a mobile app, as does Blue Pages.

This is what buyers and sellers have been looking for for a long time - Joseph Zeng, HouseSigma

"This is what buyers and sellers have been looking for for a long time," says Joseph Zeng, whose HouseSigma website was ready to go right after the ruling became public.

The traffic has been "tremendous" since Saturday, he said. Zeng said the site had 10,000 hits in half a day on Tuesday.

"After the ruling the amount of attention we've had from users is the big surprise," he said. "People say, 'We've been looking for information like this for years and years.'"

He's keeping his eye on TREB's next legal manoeuvres, in case TREB gets a stay of the order or the decision is reversed at the Supreme Court.

This is a screenshot of an interactive map on MongoHouse.com that allows users to view what the house sold for. (CBC) In the meantime, Zeng is confident what he's doing is in compliance with a C ompetition Bureau ruling in April 2016 that keeping sales prices secret is not in the public interest. His ambition is to expand the service to other cities.

A MongoHouse spokesperson who asked to remain anonymous because he fears legal trouble from TREB said his site listing house sold prices has seen 42,000 hits since Saturday and he's been approached by entrepreneurs wanting to build apps on the data.

It's been so unprecedented that the not-for-profit has had to add new servers and is looking for ways to scale up, perhaps becoming a national site.

He suggests relieving the burden on TREB of holding sold information by shifting it to a central public agency, similar to Open Data Toronto.

"It's not right to ask a private sector agency such as a real estate board to maintain such a database. If it's public information, it should be maintained by the public agency," he wrote in a blog post.

Opening a door for innovation

John Pasalis with Realosophy Realty in Toronto says he'll wait until the legal battle is over before releasing information online. (Realosophy Realty) The court ruling last Friday opens up the door for more innovation in the real estate sector, including discount real estate brokerages and online services. Information such as commission rates, previous listings or sold prices on the same property and transactions that haven't closed can be made public.

John Pasalis of real estate agency Realosophy welcomed the court ruling, but is holding off putting sold prices online. Instead, agents share sold price information only with clients in the way they always have.

"We're not rushing to publish. We want to go by the rules for now," he said.

Wait and see

There's a risk TREB will have its request to stay the order granted, which would mean taking down the information after a short period, he said.

And as a licensed agent, he wants to remain on good terms with TREB and work toward creating a set of rules that would work for everyone.

The "anonymous websites" that are already publishing probably have only short-term life, he said.

"The consumer is going to be more educated and be able to make better decisions. I think that's the important thing,"