See http://help.yahoo.com/l/us/yahoo/search/basics/basics-04.html if you want to use advanced query syntax. U.S. won't crop up very often as most U.S. sites use generic (.com) TLDs, whereas this Pipe is based on country-code TLDs (.mt, .ar, .es, etc.). It is a useful tool if you use it well :)…
Lists groups that user FROM is in but user TO is not, linking to group’s “join” page. Does not really “copy” groups, but takes you half-way. More info at http://flickr.com/groups/flickrhacks/discuss/72157605523124294/
Searches photos uploaded by a specific Flickr user by the date they were taken. Photos are tagged with datetaken:min and datetaken:max as specified in www.flickr.com/groups/flickrideas/discuss/72157603784395061/72157603875001211/ will show up in these search results on the basis of those tags’…