One option might be to just sort the scored items by bookmark/dateAdded so related newest bookmarks float to the top.

Another beginning might be to just increase score if the item falls within the range in either the bookmark/dateAdded or the history/lastVisited.

This probably covers many useful scenarios e.g. I recall bookmarking (or visiting) a page regarding regex within the last 12mos, so that related item should float to the top.

Note: I haven't played around enough - it might just naturally do this anyway if the order being returned is based on how recent the item is in history or bookmarks!