I'm pretty sure this was on accident, I saw a post saying the admin said a data disk crashed.
the tags are one of the only way to see ur history but the dates are all weird as hell i dunno why
Some people get notifications, some don't. i'm fortunately one of the lucky few who still got them. I don't think you have to rerecord everything, some peoplee are getting their lists back slowly

While the mangago server was down did they purposely erase all the data from users or has this been done accidentally?
For example my "I already read" list is wholly gone but all of the tags I've used are still available. Through the tags I could see that all of them are dated "1969-12-31" which is obviously strange.
Also does this mean I will not get a notification anymore when they are updated? Do I have to rerecord all of my 800 already read mangas?