I'll try to clarify and give super-brief history:
- In the past, there was no good option for those outside of proximity to the city centroid, nor for businesses which didn't have street addresses.
- Yes, it used to work. In fact, in 2007 at SMX Local conference, Michael Jones, Google Earth's VP, suggested that renting a post box to get a street address was a good solution.
- Since then, Google stepped back from that advice and began recommending against doing that.
- They've now begun offering the ability to designate service areas, so businesses without addresses or with street address outside of city limits could have a more equitable chance of appearing in the search results.
- So, yes, UPS box rental works. However, it shouldn't be necessary anymore, now that Google's rolled out the service areas solution. It would be very easy for Google to obtain a list of UPS mail store addresses and use that to devalue location impact for companies using it for unfair advantage.
While Google's solution is still new and has reportedly had a few hiccups for some people who used it so far, it's going to be their approved method for handling service area, and one can expect that it would likely be the easiest approach to marketing when street address is nonexistent or outside the main city limits.