'Stream in' is an idiomatic expression which means to run, pour or flow into a a place - like water running in a river. This expression is usually used to talk about gases or liquids or the movement of people through space.

1. Following the singer's amazing television performance, the recording offers came streaming in.
2. As soon as I launched the new product, orders started to stream in.

1. When the final item was revealed at the auction, the bids just streamed in and the auctioneers made a fortune!
2. If we promote this product correctly, our profits should just start streaming in.
3. The new product kept malfunctioning, so the complaints started streaming in from day one.