How does it work? Let me quote the process:
The problem is the differences between how the Post Office interprets addresses and how Google places interprets addresses.
If I create a new listing in google places and I give it this information
Name: Maximum Enterprises Street Address (1st line) : 100 W. 1st Street Street Address (2nd line): 225 E. 9th St. Suite 101, #9876 (my note: this could be any deliverable address PO Box, UPS Box or Street Address) City: Los Angeles State: California Zip Code: 90112
Then I select “Verify by mail.”
Google sends the PIN number with this address:
Maximum Enterprises 100 W. 1st Street 225 E. 9th St. Suite 101, #9876 Los Angeles, CA 90112
Here’s what happens. The Post Office eventually delivers that PIN# to the UPS store at 225 E. 9th St. Suite 101 (it will take a bit of extra time for handling, the ZIP code is actually wrong for the UPS store, so it will kick around the Post Offices a bit before it eventually gets delivered). The guy at the UPS store puts in in box 9876 (fictitious box #, he’ll probably trash it or return it, but if I had an actual box there, and used that number for my address on Google, it would go in my box).
I get the PIN and verify it, and Google places my location marker at 100 W. 1st Street (49 feet from the point that Google uses for “Los Angeles, CA”).
The post office delivers to the last address line, the line on the envelope closest to the ZIP code. Google places the marker at the first address line. This difference in handling allows anyone to “verify by mail” for any address they want to use that is in the same city as their actual mailing address (or a UPS store/Virtual office location in that city).
Pretty amazing, right? And it works, Mike tried it.
In a Sphinn thread Mike asks if what he did was ethical. Jill Whalen, a prominent SEO, replied saying:
Sure, why not. That can help Google fix things, but in the meantime, everyone else can take advantage of the loopholes!
By making Places Pages so prominently featured in search results right now, Google has opened themselves up to mega super duper spamming. For some, it's going to be the only way to compete with Places Pages.
Even I'm not discouraging clients to have address/phone numbers in the various locations where they operate, as it may be necessary (if not already).
I don't think this is a good thing, but it's Google's bed that we have to lie in.
Forum discussion at Sphinn.