diff --git a/README.md b/README.md index ef1b724..8eb7f48 100644 --- a/README.md +++ b/README.md @@ -133,12 +133,15 @@ The topics will be inferred by the browser. The browser will leverage a classifi * Please see below for discussion on allowing sites to set their own topics. * The mapping of hostnames to topics will be updated over time, but the cadence is TBD. * How the top five topics for the epoch are selected: - * At the end of an epoch, the browser calculates the list of eligible pages visited by the user in the previous week - * Eligible visits are those that used the API, and the API wasn’t disabled - * e.g., disabled by preference or site response header - * For each page, the host portion of the URL is mapped to its list of topics - * The topics are accumulated - * The top five topics are chosen + * Topics are sorted by a two-level sort – first by priority level and then by visit count. + * Priority: + * Each root-level topic (e.g. /Arts & Entertainment or /Autos & Vehicles) in the taxonomy is assigned a binary priority level based on industry input. The root-level topic’s descendants inherit its priority. A topic’s priority is universal across all epoch calculations for all users. + * Visit count: + * At the end of an epoch, the browser calculates the list of eligible pages visited by the user in the previous week + * Eligible visits are those that used the API, and the API wasn’t disabled + * e.g., disabled by preference or site response header + * For each page, the host portion of the URL is mapped to its list of topics + * The topics are accumulated * If the user opts out of the Topics API, or is in incognito mode, or the user has cleared all of their history, the list of topics returned will be empty * We considered a random response instead of empty but prefer empty because: * It’s clearer to users to see that after disabling the feature, or entering incognito, that no topic is sent