Google Hacks, 2nd Edition

Spot Trends with Geotargeting

Compare the relative popularity of a trend or fashion in different locations, using only Google and Directi search results.

One of the latest buzzwords on the Internet is geotargeting , which is just a fancy name for the process of matching hostnames (e.g., http://www.oreilly.com) to addresses (e.g., 208.201.239.36) to country names (e.g., U.S.). The whole thing works because there are people who compile such databases and make them readily available. This information must be compiled by hand or at least semiautomatically because the DNS system that resolves hostnames to addresses does not store it in its distributed database.

While it is possible to add geographic location data to DNS records, it is highly impractical to do so. However, since we know which addresses have been assigned to which businesses, governments, organizations, or educational establishments, we can assume with a high probability that the geographic location of the institution matches that of its hosts, at least for most of them. For example, if the given address belongs to the range of addresses assigned to British Telecom, then it is highly probable that it is used by a host located within the territory of the United Kingdom.

Why go to such lengths when a simple DNS lookup (e.g., nslookup 208.201.239.36) gives the name of the host, and in that name we can look up the top-level domain (e.g., .pl, .de, or .uk) to find out where this particular host is located? There are four good ...