There are three types of comments you will receive when you start your webcomic (well, four if you count no response at all.): The short affirmation, the critique or constructive criticism, and the nasty remark.
The short affirmation is what you will get most of the time. It is when you ask your friends or family what they think of your comics and is usually only a few words that basically mean, “I like your work and you should keep doing it if it makes you happy.” The short affirmation can also come from fans that read your comics and want to tell you how much they like it. These comments are the most wonderful thing you can receive as a comic artist, especially if you receive one every other day. Cherish them. Whatever you do, no matter how busy you are, you should try to respond to every single one of these even if it is just to say “Thank you.”