One issue that I had is what I believe to be, loosing the new website bonus from google where google will rank new websites with fewer backlinks higher than older websites with the same number of backlinks. If you look at this chart according to google analytics, you can see this seemed to happen around April 20th for me, which was annoying because my website taking off all of a sudden and then collapsed.
(visits from google)
New information that gets posted to my website is getting ranked several pages down where it used to be near the top.
Luckily other sources have picked up and in that time I was able to get a fair number of loyal users who have carried the website since then but google was a very important traffic source to me and my new registrations is disgustingly vacant (so much of a decrease I hardly want to discuss it).
I'm wondering how the new domain will fare and will I be given another beginners bonus or will it treat it as the same website (assuming I do a 301 redirect). If I don't do a 301 redirect, it may be worse because google may assume I stole the information from my old domain.
Anyways I'm looking for information from those with experience since many of you have been running forums for years and must have encountered this at some point.