Thanks @kildor for respond. May be someoe else from Russia would like to say something?
To say truely, I have no idea why iNaturalist become so popular in Russia. Well, it’s actually not so popular as it could be (or as you could assume). Currently, we have only 6K+ observers (and only 5K+ were active in 2019 & 2020). Well, there are many very active and hardworking observers with tons of observations, who made their archives available via iNat.
Why they have chosen iNaturalist? In some cases, they migrated from other platforms. iNat made them sure that they can upload their huge archives quite efficiently and smoothly. On the other hand, Russian language interface curated by Katya is a great deal. Also, our project “Flora of Russia” is permanently in the list top-5 (or top-6) recommended projects (thanks iNat stuff for posting it among recommended projects).
In 2019, PR-department of Moscow State University distributed three press-releases about our botany activity in iNat all around Russian media. I guess this helped much as well. Also, I’m always promoting iNat among professional scientists avoiding the wordings that iNat is primarily for citizen science. It is for everyone and could help scientists as a wonderful platform for data collecting and management.
There’s extremely active community of birders as well. Plant hunters are not posting much birds, where as birders made a lot of wonderful observations of plants.
I agree that for plants a community of experts was really an advance. At the moment, top four experts for Russian plants are professional scientists from Moscow University. Altogether they made 170K identifications and I guess many for plants from outside Russia.
There are some diproportions in spatial coverage. Russia is a huge country with sparse population in Siberia and the North. Probably, these stats could be interesting: https://www.inaturalist.org/journal/apseregin/30522-statistika-proekta-flora-rossii-flora-of-russia-po-sub-ektam-rf-na-09-01-2020