He is saying that users could see the data where everyone wanted a notif. If there is a pool at 4 but not at 5 then making a spend at 5 would be wise because once at 4 the fees go above 5. Kinda non betting betting market.
A market for alerts?
The legendary nostr:nprofile1qqsgk539zq9ercdt86rv5r3qnzarmsyca4gnuc7d728p5cq05q9xkrgpp4mhxue69uhkummn9ekx7mqpzfmhxue69uhk7enxvd5xz6tw9ec82cspzamhxue69uhkummnw3ezuendwsh8w6t69e3xj7s84kuwj knocked an app together.
I use it regularly to get an indication of fees.
It's obviously not using my mempool but it's just an app.

Discussion
Neat idea. I could probably add that to the app pretty easily
An alert for when the min fee reaches a certain level would be useful.
This would allow you to be alerted when fees are heating up & not just when they're cooling down.
I still don't see why other people's alert data would be useful. My alerts certainly don't indicate I'll be placing a bid for block space.
It would definitely be more useful looking at data of transactions queued… which is what the mempool.space fee rates do already… so yeah
The market for Timechain block space is arguably the only truly free market we have.
Alert settings can only indicate where people might be bidding for block space. Signed & unconfirmed transactions are still a better indicator for setting your own bid.
Mempool dot space does a great job of graphing estimated future blocks. It can get tricky to make the next block during times of high block space demand though. I don't see how alert information can help significantly with predicting this.