I see this has gone several days with no answer.
You're asking about the forum "style" or "skin", right? (As the word "service" doesn't really fit the context of your question.) The forum style is a mildly-customized vBulletin 3.something style. (Bottom of page)
What you see is only the tip of the iceberg, though......
I think vBulletin must either be: fairly difficult to dramatically change the style -or- be limited by its license. Most of the vBulletin boards I've come across are immediately identifiable since they look so similar.
I think the reason may lean toward the former. Looking at the html, there's an awful lot of inline CSS.