Watchlist & Favorites: Two Different Reminders
A watchlist tracks specific lots and listings; favorites track sellers and buyers. Both ping you when something changes.
Two related but distinct surfaces. The watchlist is "I want to know when this specific item changes." The favorites list is "I want to know when this specific company posts something new." Keeping them separate keeps transaction alerts and relationship alerts quiet enough to be useful.
Watchlist
/market/watchlist (and /auction/watchlist) shows lots and listings the user is tracking. A ping fires when: the price changes, the status changes (e.g. a market listing moves to draft, an auction enters its final five minutes), the lot is sold or withdrawn. The watchlist count is denormalized on the listing row (see channel-exclusivity guard for why this matters), so the seller sees how many people are watching at the moment of pricing decisions.
Favorites
/market/favorites is the seller and buyer list. Favorite a seller, get a notification when they publish a new batch in your category. Favorite a buyer, get a notification when their intent matches one of your listings. Quieter than watchlist; meant for relationships, not transactions.
Notification preferences
Both surfaces respect the notifications preferences. A user can subscribe to in-app pings only (no email), or roll everything into the morning digest (no realtime), or full firehose (every change, immediately). The preferences page is per-user, per-event-type.