Google

Google offers a great many products and services, some of them interesting.

Places - Local search and geolocation

"Each business listing on Google is in fact a giant 'cluster' of information that we get from a few different places: Yellow Pages, for example, as well as other third-party providers. However, the basic information that you submit through Google Places is the information that we trust the most. This means that it will appear instead of any basic information that we get from anywhere else. To make sure the basic information you submit is accurate, we'll ask you to verify it first by entering a PIN that will be sent to either your business address or phone number." You can add other information to your listing too — such as a description of your business, for example, as well as photos, reviews, or information about hours and parking costs — that will also appear above similar information from other providers." - http://www.google.com/local/add/analyticsSplashPage?pli=1

• other sources:
  • Localized search - Localeze.com / getfave.com, Bing, Wolfram Alpha, Google correlation corpora
  • Online directories - YahooLocal, A9 YellowPages, YP.com, CitySearch, Yelp
  • Prosocial networking - MerchantCircle.com, Yodle, ReachLocal, OrangeSoda
  • Geosocial networking - Facebook Places, FourSquare, Flickr metadata, Gowalla, 40000 stupid companies
  • PDAs / intelligent software assistants - Siri (Apple), TomTom, smartphone mapping apps
  • GIS / collaborative mapping - OpenStreetMap, anything using Google Maps API
• Quality Guidelines, User Guide