Mike Blumenthal reports Google is limiting some of the verification options for new businesses.
If a business is "new to Google" then Google may require a physical post card be delivered to the new business for verification the slow way. I assume this is just an additional form of Google spam prevention.
The quote Mike has from Google reads:
I understand there have been some recent questions about verification methods. If a business is new to Google, certain verification methods may be unavailable depending on the information provided for the business.
Of course this will delay the process for new businesses to authorize their businesses with Google, but I also hope this helps reduce some of the Google Maps spam.
Forum discussion at Google Places Help.