Systems and methods are described allowing dynamic selection of media items for presentation within a media stream based on dynamically-generated information that describes the content of the media stream or the stream's consumer. Systems may include meta data servers and media servers that work together to dynamically select media items and dynamically build a media stream containing the selected media items to the consumer. The media items are selected based on dynamically-generated meta data. Such meta data may be generated by previous consumers of the media stream and provide an accurate and dynamic description of the contents of the media stream. Because the media items are dynamically selected based on dynamically-generated meta data, even though the same media stream may be requested by different media consumers, each media stream is individually generated and may be a unique stream that reflects the impressions of previous consumers of the stream.