after 10 years, Stack Exchange banned my accounts:

http://meta.stackexchange.com/users/177247
http://serverfault.com/users/114642
http://stackoverflow.com/users/1002260
http://superuser.com/users/71001
http://unix.stackexchange.com/users/17307

and they refused to provide any explanation. After filing 9 appeals, they finally sent this message:

you also used them to violate site rules and upvote your own content

which is not true. I offered to cooperate and provide evidence to clear my name, but they have since broken contact (two weeks), and are just ignoring me.