I know that many people don't like complex or intransparent recommendation algorithms.
Currently, there are "subscribed", "local" and "all" categories (at least in the default lemmy web UI).
I would like to change this to include custom topics ("listings"). They are a custom way of choosing content (in case of Lemmy listings). In Lemmy, custom listings appear just like standard listings (API-wise), just that instead of "https://discuss.tchncs.de/?dataType=Post&listingType=Subscribed&sort=Active" you have "https: //discuss.tchncs.de/?dataType=Post&listingType=list:AAAA4865698@lemmy.world&sort=Active" or something.
Listings could either be lists of communities and other listings. Consider this simple text file to describe a listing for a memes-topic: (that contains 2 communities, everything on 1 domain, and another sub-listing)
c:memes@lemmy.world
c:memes@lemmy.ml
domain:memes.net
list:AAAA4865698@lemmy.world
Or they could take their data from an RSS stream or similar external source.
How about open source pluggable algos which can be optionally marked shareable between users and selected from a list sortable by number of "installs"
So like a user could define an algorithm to select posts, and then mark it shared, and other users could see it in a directory and try it out themselves, and optionally clone and hack on it, release a new version, etc.
As far as how the post selection algos could be defined, I'm thinking of something similar to the boolean query syntax in the Quod Libet music player, but one could also implement a more code-like syntax.
(I'm aware this is a huge ask, but I've had this idea for 8 years since my first Mastodon account, and have been too busy being oppressed by life to do anything about it.)
Yeah I'm personally tending to always separate data and processing.
Data means you have an underlying data source (in lemmy's case the set of all lemmy servers hosting lemmy communities), and a separate system that does search/recommendation based on the data.
The search/recommendation system would not store any data itself, but only filter and sort and process the data from the underlying servers and communities.