Possible to permit posting w/o giving email address?

[MrJamesBond007]

I am starting a board. I am concerned that users might be reluctant to post if they must give their email address - which may stifle growth. Is it possible to set the board so that a user can post a question or comment either (1) without giving an email address or (2) without any type of registration? If so, are there major disadvantages of this approach? Thanks

[RedeemedWarrior]

very possible to allow guests to post

downside

is huge

spammers
trollers
Porn
Malware links