The data URL scheme is pretty cool. It's only supported in a few browsers, mozilla included. That's ok, because you probably wouldn't use this generally anyway.
Last night I wrote a scraper for a website, storing data into a MLDBM/DB_File database. Some of the important data included images. I just stored them in the database Base64 encoded. That made it very easy to output customized HTML pages, with inline data: IMG's.
