For some people, hearing a particular song immediately conjures up thoughts of an old boyfriend or girlfriend. For others, it's a place — a park, a street corner or a restaurant. So instead of making mix tapes, they're making personal maps, using the friendly technology that Google uses for its mapping feature.
At platial.com, a new Web site founded by "psychogeography hobbyists," the result is something like Wikipedia crossed with Rand McNally. Hundreds of "platial explorers" are contributing maps that trace everything from their first heartbreak to good birding spots. Venture capitalists like it, too.