It would be nice if we could make readings public so we could show it off to other people...

Actually, if you view the source of the Plant's View tab of your readings, you'll see in the html for the graphs is a url for the xml_source. For instance, I have a reading at http://easybloom.com/readings/12367 and the raw xml for the sunlight readings is at http://easybloom.com/chart/12367/data/light