[cstejerean]

Comments get downvoted if they don't add to the discussion, and particularly if they're off topic from the thread they're on. Asking how posts get negative value is a fine thing to do. Create a Ask YC post and someone will gladly answer. Asking this otherwise reasonable question in the wrong place however can lead to downvoting.

Everyone makes mistakes occasionally and gets downvoted (sometimes it's unfortunate but you can just get downvoted for expressing an unpopular opinion). But hopefully in the long run you bring positive value to the site and your comments are voted up more often than down.