Over on Dynamically Typed today, there's a new posting from Harry concerning Flickr (the image hosting service) and how they use PHP to enhance this service.

Some interesting quotes: Stateless method-call APIs are easy to extend, [Unicode] It's really easy, Normalised data is for sissies ... Keep multiple copies of data around ... Makes searching faster. Would be interesting to hear more from Cal on the other side of scalability - what's it like to maintain "~60,000 lines of PHP code"?

What makes Flickr interesting as an online application is it's use of RSS, among other things, and how that in turn enables social networking.