Killer #nostr client idea: allow following and muting people based on their npub AND keywords (plural)

This would enable users to follow someone, but only when they post about a particular topic.

Or, see a person's posts except when the talk about topics X, Y or Z.

This is different than following someone and then muting a particular word. It only applies to that person.

If one were really crafty, this could override muted words. For example, maybe you generally don't want to hear about pizza, so you mute that word. But when Papa Del posts about pizza, you absolutely want to see that.

Once this code is written, it makes all kinds of other customizations possible:

1. Follow "pizza" but only if it also mentions "pineapple"

2. Mute "Nixon" unless tge post also mentions "prison", "jail" or "trial".

And so much more. This is the killer feature because it puts the user in control. It gives them more power over their feed than any other social media platform.

Furthermore, because nostr is more than just social media, the same code could be reused to filter out products from a particular seller, get notifications when someone is available to do ridesharing, and so forth.

Who does this appeal to? Users (obviously) but also people who actually produce stuff. They don't have to have one account for permiculture, another one for cryptography, another for mesh radio gear, etc. They can mush it all together and the users can get juat they things they want (which very well could be all of it, as it is now). Creators could still have brand accounts, but they wouldn't be punished if they don't go that route.