I'm a freshman graphic designer, and in class we are learning how to use Adobe GoLive. Does anyone know how much this web design program is actually used in the real world? What are the most used web design programs for professional designers?

I haven't even heard of it.
It's probably used a lot if it's expensive...who knows
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Adobe GoLive isn't as popular as Microsoft Frontpage and Macromedia Dreamweaver. Adobe is more popular for Photoshop and Illustrator and Publisher.

what does "GO LIVE" do?

The same thing as Dreamweaver or Frontpage. You can make a website without having to know how to code. The only difference is that it was made by Adobe. (Go Adobe!!!)