@lukasros Network size is relevant to the problem only as an upper bound on data sources.
It's the number of sources followed by an individual user that creates a purely local problem. Networks have worked to exacerbate it by suggesting they follow five more sources every time the user blinks at the site.
Even then, it's not number of sources so much as something like mean number of posts per day and variance across the means between those sources followed.
The vacation photo bomb problem could be solved by "auto-foldering" rather than leaping to a purely algorithmic feed. Seems a spurious justification.