Looks like the communities probably gonna get pretty split up over what platform they use. It was nice with the first year or whatever of Evo where everyone and every track was all in the same place, but its definitely not a bad thing releasing the game in as many forms as possible. Personally I'll probably get it on 360 or PC (as long as it looks good enough to buy which I imagine it should) as I might hold out on getting a PS4 (no X1 for me) considering I have only just bought a good computer.
Something I wonder though is that its called Trials Fusion and presumably this is a reference to the link between this game and Frontier, but I can't help but be curious whether maybe its a reference to the fusing of Track Central amongst all the platforms.. I don't know much about cross-platforming though so I have no idea if this is possible (or if the different console companies would want/allow it). I know PS3/PC cross-plat'ing exists for Portal 2 though.