flickr services and api

Most of you probably know that Flickr is a popular online photo sharing
service, which is, along with Gmail, considered to be as, or more, capable
than many desktop alternatives. As I was studying their web application
service and design, I found that they expose an API, (with pretty good
documentation :) ):

http://flickr.com/services/api

Here is the main Flickr services page, which gives examples of cool
applications that have been built using their API:

http://flickr.com/services

Flickr has an open Application Programming Interface (API for short). This
means that anyone can write their own program to present public Flickr
data (like photos, tags, profiles or groups) in new and different ways.
There’s a long list of API methods available to you to work with, and we
love it when this happens, so… go forth and play!

It seems that this is the next generation of web application… (iTunes
is also a similar application, using newsfeeds to generate listings of
music, etc.).