It sounds as if someone just dropped a tricycle into a meat grinder. I’m sitting inside a narrow conference room at a research facility in Bristol, Connecticut, chatting with Joseph Longo, the founder and CEO of Startech Environmental Corporation. As we munch on takeout Subway sandwiches, a plate-glass window is the only thing separating us from the adjacent lab, which contains a glowing caldera of “plasma” three times as hot as the surface of the sun.

A: Tagging is the act of assigning your own keywords to things online—photos, blog entries, bookmarks—so that you can easily categorize, locate, and share them in the future. One of the best examples is del.icio.us, which lets you save Web bookmarks to a page on the site instead of to a file stashed away on your computer. This way, you can access them from anywhere and let other people see what sites you like.