we all love steem :)
Here are some detail about Sai oracles:
Price data comes from trusted devs who get the data from multiple market API's. Price feeds are sent to a contract called medianizer that will take the median (or the average of two medians if the number of price feeds is even) of the inputs. The price is updated when the last price changes 1% or more.
RE: Maker Meeting Notes 2017 June 4th