I've used stackoverflow and I could see a problem is building a repeat visitor community or scaring new users with that format.
I actually like the old audiworld format/new quattroworld format. The forum is like an outline. Each response to a thread is indented to indicate who is talking to who. This lets you scan every post without having to scroll by it like an inline format like the default vbulletin. You can change the view format of vbulletin but the problem is that people aren't used to it. People have enough trouble using forums as is.
For my sister site
www.evwaudi.com, the only VW, Audi, and Porsche EV and hybrid site out there, I've decided to use invision power board because the current vbulletin is no longer usable and they raised the price a lot. Upgrading vbulletin forum software used to be only about $50 which gives you an idea of how disrespectful it was to the users on "other" forums I visit that they hadn't upgraded their software in about 5 years. A main competitor site misspells "Touareg" on their front page which gives you an idea how much thought and effort they put into their site. Then again, Touareg is hard to speel

VWvortex was locked into their forum software as well.
I'm using an old version of vbulletin because of the current version of the software is straight out bad. One example is that Vbulletin added advertiser support for the forum but their terms of use let them collect information on how the ads are doing. Since they run many competitor forums, this gives them the right to basically stealing trade secrets. They also have a clause that lets them take a percentage of ad revenue. It's currently set at 0 but it's outrageous that they even have this setting and raises the question of when they intend to change it.
I haven't put up the EV and hybrid forum yet because I am already working about 10 hours/day on developing both sites and researching information, (At a previous job I used to spend well over 100 hours/week on work. Although it sounds made up, working weekends increases work hours by 40% and a DVR lets you cut TV watching time by 1/3 by skipping commercials.) but I think it'll be a good niche to occupy and the quality of information I have there already is better than anything you can find on the internet on VW and Audi hybrids. For example, I've learned that 98% of car review articles test drive the car and just copy/paste what's in the press releases. The buying guides on this site and what I'm working on for the EV site contain information that you can't find in press releases and technical data beyond what you can find in normal car reviews