The SAS Profile has been used for years to sign into the JMP User Community. As of today, the Community will begin using My JMP ID instead of the SAS Profile.
So, what does this mean? When you click Sign In, you'll be directed to the My JMP login page that no longer uses a password to sign in. Instead, you will be prompted to enter a verification code sent to your email address. From there, follow the prompts. For the full explanation, check out this blog post from Ryan Gilmore that explains the whole process.
If you have a Community account and are prompted to create a new username after signing in, email Ryan so that he can link your email address to the existing account.