Nope. Never a fair representation.
A band's fan messageboard is a self-selected sample of the mingiest, mongiest saddos who have decided that they like X band so much they're going to talk about it all day. And I include myself in that, by the way. While this may include some of the most dedicated fans, it will not include the majority of the fans. How many people do you bump into at DT gigs that even know the message board exists, let alone use it? There are always a few, but rarely a lot.
Messageboards are insular - teeny little fandom appendices. They've got a deeper sense of entitlement than other fans, they've spent a lot of time articulating their grumbles (to the extent that they're magnified), and they're... I want to use the word "incestuous," but it's got too negative a connotation.
The thing is, most fans won't even think about how boring Scarred is, or how Octavarium has a lot of filler, or how Learning to Live isn't as good as everyone says. They'll briefly have a negative thought, and then rock out to something like The Dark Eternal Night. On a messageboard, though, that thought becomes positively claustrophobic. Recycled and tossed and turned until it's exaggerated beyond all belief.
Not to mention, that messageboards generally attract like people. BlobVanDam's a good example - he decided that he didn't match the profile of the average poster particularly closely, so he left. That's what I meant by "incestuous" - discussion fosters consensus, and constant discussion encourages re-evaluation, often with past discussions echoing through the re-listener's mind, and so you'll try and find things to love in tracks that are "instant classics omg how could you not like that!!" and, possibly, see the "absolutely crap" tracks through a new lens that might take the edge off it. And if you don't feel at home, you'll leave. See also: Blob.
Thing is, I actually know quite a few DT fans outside of here. Counting on my fingers... well above, say, ten, purely through happenstance. Among them, one won't listen to anything before Scenes from a Memory because it's "all really dull." A perfectly valid opinion, but he'd be laughed out of town around here. Spoke to another once and discovered that In the Presence of Enemies Pt 2 was her favourite song by the band. The correct response to that isn't "Ouch, really?" or "lol" (and when people quote an opinion on here and say "lol" I'm generally, somewhere at the back of my mind, quoting their post in turn and saying "prick"), it's "oh, grand!"
Fandom is a curmudgeonly corner of the internet which has invested just a little too much into their favourite band. Their expectations are set sky-high, only to be pummelled back down with each consecutive album that doesn't feature lyrics by John Myung (XI's the limit!), and they've got a faintly creepy obsession with a man who left the band sixteen years ago.
They're also fantastic. But are they normal fans? Dear god no. No fan messageboard ever is, in any meaningful way. Slightly more representative than usual with a cultish band of DT's ilk, but frankly Jordan should read this messageboard, laugh, and disregard everything we have to say. (Yes, including this post.) Way too insular. Break out the iPhone, Jordy. The real fans love it.