The junior/member/senior is simply post-based. This works the same in pretty much any forum software package - they just use different names and numbers. So, when you start, you are a junior member. Once you reach 100 posts, the junior prefix drops off. Once you hit something like 200 or 250 posts, you get the senior prefix added. I believe there are similar numbers to reach the advisor status. As for becoming a moderator, that is completely at the discretion of the forum administrators. Of course, if you post too many, you just get the tag of 'Registered', like Pando
So, except for the titles involving 'moderator' or 'administrator', they are simply post-based and rather irrelevant. They only reflect how much one talks, not how much one knows.
Question 4 - highly doubtful that *any* forum software has such capabilities, but I could be wrong. More to the point - why would anyone care who has websites and who doesn't?
...it shows 'Currently Active Users'. Of course, that only means that thos people have a browser window open with the forum up - which I ususally do all day long - that doesn't mean I'm actually reading every post all day long.
Also on that same page, you should see another forum called: 'Feedback and Questions Regarding this Forum', where, as marist89 suggested, you may have better luck getting such questions answered.