When logging in to MY, I usually used
miyodeya.com/users/login, just because it's easier to type than
judaism.stackexchange.com/users/login, and faster than going to miyodeya.com and clicking my way through to the login page.
For some reason, when I tried to access
miyodeya.com/users/login, I wasn't able to log in from there -- that address took me to
http://judaism.stackexchange.com//users/login, and claimed that the page did not exist.
judaism.stackexchange.com/users/login still works.