From MozillaZine Knowledge Base
Firefox 3 introduced a number of improvements to the Location Bar. Among them were changes to how sites are ordered in the dropdown menu. Firefox takes into account how frequently and how recently sites in the browser history were visited, combining them into a statistic called â€œfrecency.â€ The frecency of sites is calculated when the browser is idle. The way frecency is computed can be tweaked by a number of preferences.
A number for the frecency of a URL is calculated by letting each visit to the URL be worth 100 points, dividing the sum by the number of days since the first known visit, then multiplying the result by a multiplier based on the last n visits. The multiplier helps â€œageâ€ results, placing a higher rating on sites visited more recently. This preference determines nâ€”the number of recent visits used to calculate the final multiplier.
Possible values and their effects
The number of history visits to use when calculating the final multiplier in the frecency computation. Default value is 10 entries.
First checked in
Has an effect in