The UI locations for popular options (such as finding the forum link), finding the link to register from a forum post, is totally counter intuitive.
As an example there is no register option on the login form, and I had to guess I might get the option by clicking on the logo (taking me out of the forum) as there were no other links about how to register, or where the form was.
There is space in a desktop browser window to have the most common options appear without extra clicks, and random guesses.
The second not much of an issue, but these are really totally at odds with how well designed community driven sites are designed -from a UI accessibility perspective. Things like registering, and the forum links should really be crystal clear