Remember that Town Of Salem breach earlier?
Yeah, well, if you were affected, then as if right now there is a 27% chance that your password is unhashed. (Now readable)
Devs.. don't use MD5 for hashing, but if you must, salt your passwords.
Everybody else... You don't know what kind of password security any given site is using so make sure that the password is unique and not guessable on another site.