But I can tell it must be a very tough business. For one they have run continuous TV ads for years. The ads are targeting sellers only almost, and the main message is to save on realtor fees. So I'd suspect it's the listings that are the challenge, in a seller's market, the buyers will come.
Their offers/pricing for sellers is very thorough. Yard signs of course, but also pro photographers sessions, 3d virtual visit thingy (check it out its neat), full legal services to complete the transaction... Their online listings and overall experience is much better than MLS/Realtor websites.
In the end the platform was bought by PurpleBrick which is a slightly different business model I believe, and PurpleBrick was bought by a large credit union that might simply advertise mortgages? They never attempted to expand much outside of the quebec market afaik, but the platform looks like it's here to stay and going strong here.