Places that offer free stock market data often license it for a low fee, or take free historic data and redistribute it (as permitted by the exchanges).
If you want real-time data, you usually pay for it, or utilize snap quotes, both usually available by most brokerages. Features such as streaming Level 2 Data and Time and Sales data often require a premium subscription by the brokerage. This is to offset their own licensing costs.
They are usually only about 25 minutes behind. Something is wrong today.
