I just signed up using another email account so I can test things using a unprivileged account.
Some parts of the sign up process are good (e.g. the email welcome from Rufus)
but after confirming my email account the first forum page I am sent to was…
I think it would be nice to land on the Categories page rather than the Top page… things would look more organised for a first time visitor.
I agree with @Stephen for the page for a first time visitor. 
The Categories page would be better for first time visitors to take off.
I would like to add that upon sign-up, new users cannot immediately post new topics. So far, this is quite frustrating for me, as I don’t even know what to do in order to gain that right…
The access control system of the OKFN forum is really frustrating. I use lots of Discourse forums, but I’ve never seen settings like these before. I visited the forum for seven days, read more than 200 messages, and answered in some topics. However, I am still not allowed to ask my own questions (start a topic). 
Edit: Now I have been given permission to start new threads.
