Ok let's say I have a website. The website grows pretty amazingly, gets a very high page rank, tons of backlinks, a good solid amount of traffic. Everything SERP is great. However, the design of the site is not making the money I was looking for. Now let's say I change the complete layout and everything the site was about. Let's say: Forums -> Articles. Will the new site rank very high in page rank, if I swap the key words and put it in a new category or will I have to work my ranking back up? any insights will be appreciated.
Changing the name wont have a HUGE effect. But if you are going to change the URLs around then it could if you dont do a redirect.
if you don't delete the previous content, just change your homepage and also link to previous content then it's not harmfull
I would keep the old content linked but then branch off and begin the new topic. I would also keep the same domain if possible because of the high pr, backlinks and serps.