I don't think this is about a niche but rather a broader need for lists, more specifically, integrated lists from users. Pinterest, for example, is built around lists, Amazon has wishlists, IMDb[1] provides movie rankings, etc.
From a data portability perspective, the real challenge is getting users to connect all these platforms to a kind of unified list, making it accessible for queries, machine learning, or other applications. This, in my view, is a traction problem rather than a technical one, independent of whether it justifies a business. FriendFeed[2] was a very interesting project where users could connect their profiles with many services and their followers saw their updates. It seems their Tornado web server keeps getting updated [3].
More than a decade ago, I explored some of these ideas [4][5], conceptualizing a directed acyclic graph (DAG) model where data operations could be performed at a global level, dynamically recalculating like a spreadsheet.
Going to more complex topics there are resources such as differential dataflows [6].
From a data portability perspective, the real challenge is getting users to connect all these platforms to a kind of unified list, making it accessible for queries, machine learning, or other applications. This, in my view, is a traction problem rather than a technical one, independent of whether it justifies a business. FriendFeed[2] was a very interesting project where users could connect their profiles with many services and their followers saw their updates. It seems their Tornado web server keeps getting updated [3].
More than a decade ago, I explored some of these ideas [4][5], conceptualizing a directed acyclic graph (DAG) model where data operations could be performed at a global level, dynamically recalculating like a spreadsheet.
Going to more complex topics there are resources such as differential dataflows [6].
[1] My movies ranking: https://www.imdb.com/user/ur0601133/ratings/
[2] https://en.wikipedia.org/wiki/FriendFeed
[3] https://github.com/tornadoweb/tornado
[4] https://blog.databigbang.com/ideas-egont-a-web-orchestration...
[5] https://blog.databigbang.com/egont-part-ii/
[6] https://timelydataflow.github.io/differential-dataflow/intro...