OK, Start with Flickr. As we know Flickr is an image and online community platform where allow people to share their personal photographs. Behind the Flickr, it relies on several important technology or control system, e.g. PHP, Smarty, PEAR, Perl, ImageMagicK, MySQL4.0, JAVA, Apache Web Server2 and Macromedia flash. ImageMagick was disposed when Yahoo! acquired Ludicorp and Flickr.
Flickr do provide offical add-ons however I found some very interesting third party Flickr! add-ons:
Bubblr - transform the photo on the Flickr to comics style
Sprinklr -allow user to arrange their photos to different catalogs
Matchr - Flickr puzzle
h4ppierphotos -Flickr photos set organizer with date filter
ZoneTag - can tag your photos with the location in which they were taken
Tiltomo - image search engine
John’s Background Switcher - change computer background periodically source from Flickr!
FlickrLilli - another searching tool for Flickr
RSS2PDF for Flickr - create a PDF file from Flickr RSS
Flickr & Webimager - an screen shot upload tool based on Flickr API.
FlickrFling - An innovative prototype for exploring Flickr photos.
Flickr Logo Maker - can make Flickr style logo from user input
Loopy - Flickr-based endless screensaver
Flapper - an Flickr interface (base on flash 8)
Findr -Find photos on Flickr by browsing and refining related tags.
Clockr - check the photo on the Flickr at present time.
Retrievr - Retrieve the photo on Flickr according to the drawing that you submitted.
Most of those are integrating with Flickr photo database and give out in a Website Forms and method includes three steps: User Input-> Process -> Computer Output. I am thinking using the similar way for doing Affective Flickr as well. Website form is an good choice because is easier to manage and more flexiable.Will draw some basic structure break down on weekend.