Read/seen ranking

When track_read or track_seen is enabled on a feed group, you can use is_read and is_seen as variables in ranking expressions. On flat content feeds, enable them with activity_marks; notification feeds use their notification configuration. On content feeds, the ranking expression may only reference is_read or is_seen when the matching activity_marks.track_read or activity_marks.track_seen is enabled, otherwise creating or updating the feed group fails with ranking by read/seen status requires notification config or matching activity_marks tracking. Notification feeds can always rank by is_read and is_seen.

A mark only applies to activities created at or before the time it was set. On aggregated notification feeds, a group that is updated after it was marked counts as unread or unseen again.

For example, a custom flat feed group that sorts by popularity and subtracts 100 points from activities the user has read:

$feedsClient->createFeedGroup(
    new GeneratedModels\CreateFeedGroupRequest(
        id: "ranked_timeline",
        activityMarks: new GeneratedModels\ActivityMarksConfig(
            trackSeen: true,
            trackRead: true
        ),
        activitySelectors: [
            new GeneratedModels\ActivitySelectorConfig(type: "following")
        ],
        ranking: new GeneratedModels\RankingConfig(
            type: "expression",
            score: "popularity - (is_read ? 100 : 0)"
        )
    )
);

To rank unseen activities first instead (this does not include popularity):

$feedsClient->createFeedGroup(
    new GeneratedModels\CreateFeedGroupRequest(
        id: "unseen_timeline",
        activityMarks: new GeneratedModels\ActivityMarksConfig(
            trackSeen: true,
            trackRead: true
        ),
        activitySelectors: [
            new GeneratedModels\ActivitySelectorConfig(type: "following")
        ],
        ranking: new GeneratedModels\RankingConfig(
            type: "expression",
            score: "is_seen ? 0 : 100"
        )
    )
);

The same expressions work on notification feeds, where marks may be resolved per activity or aggregated group.

Example expressions

Aggregated feeds

On aggregated notification feeds, is_read and is_seen are resolved at the group level. All activities within an aggregated group share the same read/seen status. On flat feeds (content feeds with activity_marks, and flat notification feeds), they are resolved per activity. Content feeds with aggregation can't use activity_marks, so they can't rank by read/seen status.