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.
Past visits are categorized into four â€œbuckets,â€ based on the days since the visit. The visits in each bucket are given a different weight for frecency calculations. These preferencesâ€”of the form places.frecency.*BucketWeightâ€”determine the weight given to the various cutoffs, in points, for the four possible buckets (as well as a default weight).
Possible values and their effects
The number of points used to weight the frecency calculations of visits falling into the defined buckets.
By default, the following preferences and values exist:
First checked in
Has an effect in