3-legged OAuth makes a roundtrip to the provider to obtain a token that represents the user. The user has to authenticate and grant access to the application. 2-legged OAuth has no roundtrip. It is simply a way to send a request that is signed with your consumer key and secret to identify your application to the service. client->query($q); print_r($result); ?>]]> Array ( [count] => 100 [created] => 2008-09-12T02:22:21Z [lang] => en-US [updated] => 2008-09-12T02:22:21Z [uri] => http://query.pipes.yahoo.com/v1/yql?q=select+*+from+flickr.photos.recent [diagnostics] => Array ( [url] => Array ( [execution-time] => 555 [content] => http://api.flickr.com/services/rest/?method=flickr.photos.getRecent ) [user-time] => 575 [service-time] => 555 [build-version] => 2008.09.11.15:43 ) [results] => Array ( [photo] => Array ( [0] => Array ( [farm] => 4 [id] => 2851054416 [isfamily] => 0 [isfriend] => 0 [ispublic] => 1 [owner] => 29037411@N03 [secret] => 33955b4ee4 [server] => 3162 [title] => Uma corrente para organizar ) ...]]>