If i wanted to write a book the included certain forum posts, would there be any legal issues with doing this. Are the posts property of the poster or the site. To publish one in print would i need permission of some kind. Thanks
I would get permission. There are some possible fair-use positions that you might be able to take depending on the book itself. The problem with that is that you don't know whether a judge will agree with your position until somebody decides to sue you. As far as the owner of the post, it depends on the ToS of the particular forum. In most cases the rights work something like this, the author owns copyright but the forum owner maintains the right to display the content on the forum site. Regardless of what rights are laid out in the forum rules, unless the ToS specifically states that the author gives up all rights to the post then it will be the post author and not the forum owner that you will need to get permission from.
Yes, you would need to obtain permission and have this said permission documented. If you just obtain permission and something goes wrong (remember Murphy's Law) and you don't have it in writing you could be in serious trouble. Just be polite and ask for permission and then state that you need it in writing (email response, etc...) for your records as well as theirs.