Ok, since I don't see any threads about suggestions/feedback etc. here's one from me:
Cons:
There are, what 30 posts or threads per page? The forum overview could do with longer pages, and you might want to get rid of paging entirely on the thread views. Forcing people to change pages usually burdens the server more than not putting a limit on the SQL query anyway... In other words, like the old forums. (1000 post limit is almost the same as no paging :P)
Video embedding, but no image embedding? I think it should be allowed. With a simple style property (max-width), it's possible to limit the size of the hat brim, if that's what's worrying you. I think the lack of pictures makes the forum dull, and one thing I always liked about SL was the light spirit.
Pros:
I REALLY like the layout. It's one of the simplest forums I visit, looks serious and it's really easy to get an overview. I like the subtle avatars, spacing, font sizes, etc.
Metropolis Forums could learn from this. ;)
Also, I think it should be possible to mark your text with bold and italic. Not more than that, though. I like how the layout is otherwise forced simple.
