Neville Borg, 20/06/20 17:06:
get a batch of users (in this case, users who
participated in a Wiki Loves Monuments contest) and trace whether they are
still active or the date of the last time they used their account.
The second part of this used to be simple with Wikimetrics, now Event
Metrics.
https://meta.wikimedia.org/wiki/Event_Metrics
As far as I know, you can upload a list of usernames and get some
information about them, such as the date of registration, whether they
were active in a certain period etc. I'm not sure you can start from a
category or set of categories like WLM categories on Commons (which tend
to be quite big).
Depending on the statistics you need, sometimes it's easier to write
your own SQL query, for instance this is one I used recently for WLM-IT:
https://quarry.wmflabs.org/query/4910
By the way, a better place to ask this question might be analytics@ or
even wikilovesmonuments@ if you're just interested in WLM users.
Federico