I think this is it really. Back when I started riding trials and joined this forum (2003!) the entire internet revolved around message boards. If you were looking to find people with a common interest as you, you'd have to look for an appropriate message board, or try and find these people in person. Likewise, if you wanted to find 'How-To's' you'd come to a message board and someone there would have typed one up, or the community would know of the otherwise obscure website to go to. But now everything can be quickly done over Facebook and YouTube, and if people still can't find what they need, I bet the majorette of new web users don't even know what a forum is.
And remember back before YouTube, before Google Video, in the days of eengoedidee and Trials-Shack? The internet was spread about, but now, you can be sure everything this forum used to do can be done by Facebook and YouTube. BOTI used to be my go-to source for hilarious web content, but now it's all on Facebook and I'll probably scroll past it all at some point now.