With the addition of the hashtags, clicking on one brings up a number of pictures that share the same hashtag although this really changes nothing. Before the change, searches using regular titles did the same thing. Besides, once you click on the hashtag to see other pictures that share the same one, it disappears from the header. You can add #FlickrFriday to any picture you post in order to automatically enter the shot in the weekly photo challenge.
Flickr did what it had to do in order to compete with the other sites that use hashtags. So far though, this is limited to the iOS version of the app and we would expect it to be added to the Android variant of the app down the road.