Do I have to use steam?
Yes, the only way to login to the forums is by using steam. It helps us know who you are and means we don't have to keep any passwords or personal information on you.
Is it safe?
Yes. It is using steam's official OpenAuth system. Steam does not give us anything but your steamid and a confirmation that you own a steam account. Both of these are publically available. It means that we can associate you with a steam account and also means nothing personal is ever kept on SuperiorServers.