Find All Posts By A Single User
Two methods will be detailed here, one using the parent forum of a thread, and the advanced search (thanks to TUDJ).
Method 1 - Using the Parent Forum:
1) First to the forum that contains the thread in question and scroll down to where the thread is listed. Click on the "# of posts" for that thread.
2) On the pop-up box, find the user who's posts you want to view and click on their "# of posts"
3) You will be greeted with a page with a list of that users post in that thread starting with the newest.
Method 2 - Using the Advanced Search:
1) First go to advanced search:
2) Enter your search parameters and hit Search. To select multiple forums, use CTRL + Click.
3) You'll be presented with a list of posts matching your search criteria.