From Seo Wiki - Search Engine Optimization and Programming Languages
Geo targeting in geomarketing and internet marketing is the method of determining the geolocation (the physical location) of a website visitor and delivering different content to that visitor based on his or her location, such as country, region/state, city, metro code/zip code, organization, Internet Protocol (IP) address, ISP or other criteria.
Geographical information provided by the visitor
Different content by choice
A typical example for different content by choice in geo targeting is the Ups website at Ups.com where users have the choice to select their country location first and are then presented with different site or article content depending on their selection.
Automated different content
It is dependent on the pre-analysis of the entire IP address space. There are more than 4 billion possible IP addresses, and detailed analysis of each of them is a Herculean task, especially in light of the fact that IP addresses are constantly being assigned, allocated, reallocated, moved and changed due to routers being moved, enterprises being assigned IP addresses or moving, and networks being built or changed. In order to keep up with these changes, complex algorithms, bandwidth measurement and mapping technology, and finely tuned delivery mechanisms are necessary. Once all of the IP space is analyzed, each address must be periodically updated to reflect changes in the IP address information. This process is analogous to Internet search engine spidering in its enormity, yet requires far deeper layers of intelligence to keep the information about the constantly changing 4 billion-plus IP addresses current.
IP delivery in SEO
IP delivery for search engine optimization is the method of delivering different content to search engine spiders (also known as robots and crawlers) than to human visitors. The determination if the visitor is a known search engine spider is done based on the IP address. SEOs compare the visitor's IP address with their list of IP addresses, which are known to be servers that are owned by a search engine and used to run their crawler applications (spiders). The delivery of different content to search engine spiders than to human visitors is called cloaking and against most search engines' webmaster guidelines.
Although the search engine guidelines seem to imply that any type of cloaking is bad, there are cases where cloaking might be legitimate. The subject is very controversial and SEO experts continue to debate about when cloaking might be acceptable and when not.
"Cloaking" via IP delivery works differently from cloaking via "user agent". While IP address spoofing is harder than user-agent spoofing and more reliable, it is also harder to keep the list of IP addresses used by search engines for their crawlers up-to-date. An outdated list with active crawler IP addresses missing enables the search engines to detect the cloaking and may result in a removal of the site from the search engine's index.
- Webmasters who want to serve local content on a global domain  
- Content owners and delivery networks restrict streams based on the geographical information
- Pay per click advertisement to have ads appear only to users who live in selected locations
- Display advertisement where banner or other multimedia ads are selected to be displayed based on the visitors location. The use of connection speed data correlated to IP address to tailor content
- Online analytics identify live the correlation of city-level geography, connection speed data and certain demographic data to IP addresses
- Enhanced performance networks provide superior customer targeting to advertisers.
- Fraud prevention identifies suspicious payment transactions live by correlations between IP address and additional information (billing records, email header) 
- City advertising by advertising on web sites with extensive content related to particular cities. Such web sites can connect large city audiences with products/services for sale in those cities. Surfers searching for information about particular cities find adverts at such web sites as a result of city name related searches rather than product/service keyword searches. In this way businesses, e.g. shops, restaurants, can advertise and reach out to consumers located in the real-world localities of their product/service offerings.
- Find Personal, other's IP and Hostname GeoIP Details
- Domain name Location. IP Lookup
- IP Geolocator
- GeoIP Lookup
- Geo Ip Location
- Free GeoIP resource
- Locate IP Address
- ↑ Google webmaster guidelines
- ↑ Yahoo! search content quality guidelines
- ↑ MS Search guidelines for successful indexing
- ↑ Chris Sherman (July 18, 2001), Search Engine Cloaking: The Controversy Continues, Search Engine Watch, retrieved on December 9, 2007
- ↑ Internet World Map 2007 Study showing the geographic distribution of the Internet across the entire world.
- ↑ Internet IP Address Allocation by Country 2008 Report Study showing the IP address distribution of the Internet in 2007
- ↑ Internet IP Address Allocation by Country 2009 Report Study showing the IP address distribution of the Internet in 2008
- ↑ Credit Card Fraud Prevention Tips Top 10 Tips to Prevent Online Credit Card Fraud for Merchants
- ↑ Search Engine Optimization for Dummies, 3rd Edition, 2008, by Peter Kent, Chapter 10 'Finding Traffic via Geo-Targeting'