I was thinking of creating an ebook with content from the internet. I wanted to create a book made of forum discussions. My question is... Can I copy forum discussions from websites and turn it into an ebook to give away for free? Or do I have to get permission from the posters or can I just compile the book without doing any thing like that? Thanks for input!

You would need to get permission at a minimum from the website your planning on quoting. This is covered under the intellectual rule of property rights.

It may be no problem to get those rights to use the material. But you must represent yourself very clearly and avoid any form of misrepresentation.

Material, like those on these pages will be the property of the web site. And protected under copyright laws. And will be the same with most forums but you are free to contact their owners and get written permission if they will give it. Or sell it.