It has many echoes of the general Tumblr community from pre porn ban, same mental illnesses and all. Much more so than even twitter, and I sort of attribute it to the long form no punctuation cutesy styling that people on tumblr used. Just like that site - there's a lot of accounts with gimmicks you think are Poe's law in action but are the real deal -
https://letterboxd.com/masteroblong/ - an actual pajeet immensely triggered by western culture, yet when there's a movie he actually likes, all of those qualms go away.
I could go through the various screenshots of reviews or even the ones i didn't cap but its just not worth it in the end for me - there's something really depressing about reading a few pages of reviews - especially the top rated ones. Its not like I don't like dissenting opinions - I'm actually addicted to reading stuff that disagrees with me, but there's a mix of art school pretentiousness and banal self importance that hurts the soul. Also sometimes the horny on main fangirl reviewers can get grating - I wonder how much of a nightmare if a more male oriented site (MAL maybe) would be if straight guys horny posted the entirety of reviews - might even be funny at first.
These user based review sites suffer from all sorts of populism but enough people give an honest rating and thus serves a better shot in the dark if a movie is worth watching than RT or any individual critic - and I'll admit some reviews had me audibly laughing. Letterbox just has a much more terminally online userbase, lots of film school rejects or worse, actual film students with a bone to pick. Enough normies are flocking to it that checking out the recent reviews shows some pretty accurate or funny stuff from normal people.
I follow a few friends but also this guy -
https://letterboxd.com/vinnycenzo/. He might be too deep into the family/children's genre, but has really balanced optimistic reviews, no sky is falling rants or left wing manifestos, can seem to articulate why he loves something. I much prefer the community and wider selection of TV and online content of Trakt.com as Ged! pointed out - but sometimes filling in bullshit for the "exact time watched" section gets grating, and the easy fix of "watched at release" can make a timeline messy.