Think about these two words for a moment: "Search" and "Browse." They're words that are used frequently to describe things we do on computers. But consider their traditional associations:
Browsing is shopping, strolling, flipping through a magazine. Browsing is fun, casual, entertaining.
Searching is mechanical, trial and error, frustrating. Searching is work.
There's a powerful emotional difference between the two. Now let's talk about tags.