Gateway Page -- Also called a doorway page. A gateway page exists solely for the purpose of driving traffic to another page. They are usually designed and optimised to target one specific keyphrase. Gateway pages rarely are written for human visitors. They are written for search engines to achieve high rankings and hopefully drive traffic to the main site. Using gateway pages is a violation of the Terms Of Service of most search engines and could be grounds for banning.
GB - GIGABYTE - 1,000,000,000 Bytes = 1,000 Megabytes (Actual number is 1,024 Megabytes)
GBD -- United Kingdom Pounds (3 Letter Currency Code)
GG -- Google Guy (Google Representative at WebmasterWorld)
GIF -- Graphics Interchange Format (file.gif)
GIMP -- GNU Image Manipulation Program
GNU -- GNU's Not Unix! /g*noo/ Recursive Acronym
Google -- a search engine
Google Dance -- While the Google update is in progress, search results for each of Google's nine datacenters are different. The positions of a site appears to "dance" as it fluctuates minute to minute. "Google dance" is an unofficial term coined to refer to the period when Google is performing the update to its index. Google may be changing their index calculation method to allow for a continuous update (which will effectively end the roughly monthly dances).
GOOGOL -- 10100 = 1 followed by 100 zeros
Graphical Search Inventory. Banners, and other types of advertising units which can be synchronized to search keywords. Includes pop-ups, browser toolbars and rich media.
GUI -- Graphical User Interface
