Bruce Schneier has a write up about lock smiths in New York spamming Google Maps with multiple fake business addresses. The result is a single locksmith showing up in every neighborhood in the city regardless of the location of their actual office.

I remember this happening in Somerville when we moved in a couple years ago, so I don't think this is isolated to New York City. What other businesses would find this practice useful? Taxis, courier service... There's got to be others.