Redfin is a big pile of nothing. It's a glorified real estate agency which is itself an anachronism or soon will be.
You can easily find online or other brokers ready to "sell" your house which just means listing it on the realtors' association multiple site listings for 1% or even a few hundred dollars. The realtors association still control everything in terms of having all the data on homes for sale.
They could have some opportunity in giving buyers rebates i.e. having a 1-2% margin for buyers which most agents don't give, mostly because it's a lot luck to find a buyer than to represent the sell-side.
The idea that it's worth around 8x revenues...a low margin business as a real estate agency is...is a stretch, though to be fair, their revenues are fast-growing without that much of a marketing spend.
Not sure how their quarterly sales vary (seems like a lot in their profitability at least) but their latest quarter was terrible with only $6 mn in gross income on nearly $60 million in revenues and then $30 mn in operating expenses.
They claim to have helped users buy/sell $40 billion in real estate last year but showed just $270 mn in revenues which is something like .8% of that market value (while it should be in the 1.5 to 2.5% range I think). Not sure why that it is.