Advertising: Defining an advertisment
An advertisement has three parts:
Keywords - These are optional. If used, any search that includes the keywords will bring up one of the ads which use the keyword. If a search doesn't keyword match with any of the ads, then a random ad will be shown.
Keyword Handling - the advertisement can appear for all searches, especially those where there is a keyword match, or it can appear only when there is a keyword match. This is controlled by a set of radio buttons right below the keywords field.
Weight - Weights allow a certain ad to show up more often. The default weight is 100.
Allowed Positions - each advertisement can be restricted to a subset of the four defined positions.
Text - This is the HTML that will be inserted into your page for the ad. It should be well-formed HTML. Typically the HTML text is provided by a Pay-Per-Click program, and consists of a link and then an image inside the link.
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