In search of an easy metaphor for the Internet, one might describe it as a universe. That’s more or less the premise behind the Web site Tag Galaxy , which organizes a small portion of the net—photos uploaded to Flickr—into outer-space-themed tag clouds. The clever design features floating, glowing planets of keywords—woman, portrait, winter, Paris—that, as you zoom in, reveal themselves to be discrete pictures. (Click each to head to its original Flickr home.) Related tag clouds orbit close by, forming a solar system. The fun comes in hopping from planet to smaller planet, until you find yourself in a little corner of the universe that seems comprehensible. A search for “New York” gives you more than 5 million photos; adding “Manhattan,” “park,” “light, ” and “sunset” knocks it down to an easily browsed 33.