Also there is no MLS, there are a lot of them.
1. Try and get an offer before that window is up.
or
2. Put the listing up with enough wrong information that you get 2-3 more days to try and sell the property.
Apart from that, there's a lot of minor lying when it comes to these listings. Maybe the lot was 2 acres before it was subdivided, so you say on the listing that it's 2 acres. Maybe you jiggle the handle on the listing for the first week or so so it shows up as new/updated every day. Maybe you say that the listing has "central window unit AC" to try and confuse people into showing up.
It's mostly a lot of light treason against buyers and sellers. Real estate is a bit of a dogfight and much of it falls into the "technically illegal but not worth suing" bucket.
It's a complete shit show as of 2013. Basically anything that is on any MLS I've seen is probably incorrect.
I know there's not much that's sexy from a technical perspective about running what is effectively a tech-heavy discount brokerage at scale, but it allows them to offer a fundamentally better UX than Zulia or any of the pure leadgen sites can. And there's a huge amount of code involved in running the ops on an organization like that, which a pure search app doesn't have to write/maintain.
It's really selling them short to say their only difference is marketing.