Google Maps, local search engines, internet yellow pages and other online business directories often receive biz listing info from a great many sources and must merge it together (see my description of this in Eric Enge’s interview with me). When this happens, loads of variations in the business’s name, address and even phone number can cause listing data to fail to be merged. All this makes me think we might need a “Canonical Tag” for phone numbers! Read on, and I’ll elaborate…

Some business directories and data aggregators contain huge percentages of bad listings including gone-out-of-business companies and duplicated listings. Pankaj Mathur of InfoUSA recently estimated that some sources such as Dunn & Bradstreet, Acxiom, Localeze and Google Maps might contain 17-to-18-million records, or up to 4 million more records than actual, live businesses! That’s as much as a 28.6% error rate!

I know from experience that some percentage of a business directory’s bloat can be caused by inability to figure out if a business has closed up for good or not (most data sourc