Code:
ON infoline:JOIN:#the_channel:{
   .msg $chan $chr(91) $+ $nick $+ $chr(93) $ulist($nick,infoline,1).info
}

alias addinfo {
   .auser infoline $1 $2-
}
alias delinfo {
   .ruser infoline $1
}


Paste all of that into the remote section (alt+r), but make sure to change #the_channel to the channel you want this to work on. Then to add someone to the info list type (using your example):

/addinfo newperson Look, this is his infoline.

And to remove newperson's infoline:
/delinfo newperson

Note: I didn't actually test that code, but it should work.