Streams are more an attitude shift to match how people consume content than a substantial functional shift. They still allow for permalinks; it's possible to link to any tweet directly. Stream-oriented content is about acknowledging that pages and destination sites are the wrong units of content. Content needs to respond to platforms — more than just screen sizes. Content Management Systems need to be treated as true content management systems, not page management systems. Content == data. See: John Borthwick's comments on content as information; Substance.io and Prose; Medium; NPR's API; &c. Pages are a legacy format.