One of the most famous services for image segmentation & retrieval is (or was) blobworld. The system was built for advanced image querying based on regions (blobs), which were identified automatically. For image retrieval one could select blobs and define whether color, texture or size and position were most relevant for the query. Based on the input several good matches were presented.
Over the years Blobworld became a de facto standard for showing the possibilities of content based image retrieval systems. Hopefully there will be more innovative applications like this one in the future.