See blog post SML Pro Blog: SML Thank You / 2009-09-25 / SML about the reason this was created and brief description of how it was done. Visit the wiki page for detailed module-by-module description.
SML Wiki: Yahoo Pipes: SML Thank You
The geeky way of recording and remembering kindness and generosity from other people.
SML Wiki: SML Thank You
Pipe Modules Used
+ Fetch Feed from sources that require no filtering
+ Fetch Feed then Filter
+ YQL for grabbing Flickr items
+ Flickr general search
+ Union to merge all data sources
+ Unique to filter only unique items
+ Sort to reverse-chronological order