Where does Bigger pockets pull their listing feed from??

[Jamie Pluszczynski]

Good afternoon everyone, 

I noticed that a good amount of properties I search in Bigger Pockets property search are not appearing at all when they are absolutely on market and in the MLS. I am just wondering where Bigger Pockets pulls it's market data from? I also noticed that the pre-foreclosure and sheriff sale information is outdated in many cases, and does not seem to update as the properties move through the foreclosure and then sale process. Can anyone give me any any insight?