Yes, with NIP-32 labels (https://github.com/nostr-protocol/nips/blob/master/32.md) any content on nostr (notes, profiles, ...) can be labeled. Anyone can create these labels as (kind-1985) events. The spec does only define the structure but clients/apps need to establish what the labels will be used for.  

 Currently labels are used to add user defined tags to posts or rate relays. You can see some of the latest label events here:
https://pleb.to/nostrtool?kinds=1985&tags=&authors=&ids=&since=&until=&limit=20 

 Labels are more scalable - you can have unlimited number of them, while list size is limited in practice to something like 2k values (that order of magnitude). 

For curation labels are def better. You can even create a custom relay using your labels at feeds.nostr.band 

 I see! Thanks, that's a very clear explanation 🙏 
Then I've been bookmarking the wrong way and it's going to get real confusing to what "Bookmarking" even means. 

For notes/insights/literature I've always preferred using tags/labels as a categorisation system because of the overlap in many different topics. I thought nostr lists fixed that because I could add the same event to as many lists as I wanted (and not just one). Didn't know about the size cap. 

One question: you can have a lot more than 2k followers and that's a list too, no limit there?  

 Followers are your pubkey mentioned in their contact lists, you can have as many followers as there are pubkeys.

Your contact list is limited in size though, just like every other event kind, strfry has 128Kb max event size IIRC, others' may vary but there will be some limit no matter which relay. And the bigger the list, the more expensive it is to edit it, which makes increasing this limit not practical anyway. 

 Sorry yeah I meant follows (contact list). Very interesting to know that there's a limit there. Merci !

So if someone follows you that's quite the honour in a way (1/2000) hehe 😉.

This limit could be useful for spam protection as well. I'm going to have to think about this more.  

 Well that honor could be diluted by their ability to include you in other profile lists and switch btw them :)

Limited CL size also helps with requests to relays, when you know you won't have to ask about 100k pubkeys to build the home feed. It probably helps in many other places. But then it's a less 'general' solution than unlimited list, might limit some use cases. But then 'follows-based' home feed might just be a legacy twitter-like approach and we might end up with a very different set of "filters" to build one's main feed. Just rambling 

 1. Yop, that about that right after posting. I'm disrespecting that honour already that way 😉. 
2. I'm also betting against Follows-based feed