Since typing four tildes adds the time and date to your resulting signature, this is the preferred option for signing your posts in discussions.
Note that if you choose to [[Wikipedia:IPs are human too|contribute without logging in]], regardless of whether you have [[Wikipedia:Why create an account?|an account]], you should still sign your posts. In this case your [[IP address]] will take the place of your username, and will link to your contributions history. Your IP address might look something like '''192.0.2.213''' or '''2001:DB8:CEEE:21B:DB60:07FE:4277:63FF'''.
If, for some reason, you are not getting the above results when signing, see the [[User talk:SineBot|SineBot Frequently Asked Questions]] for tips.