Trials Fusion featured local multiplayer at launch, but online multiplayer? That was absent. RedLynx seemed a little disappointed with how online multiplayer worked in Trials Evolution, so they wanted to take their time and create something a little more alluring. The idea was that this online multiplayer component would be released as a free update later in the day. Today RedLynx went into a little more detail on precisely what we can expect from that update.
You can read the full update from Anti Ilvessuo here, but the general gist of the situation is this: the team has managed to make eight-player online multiplayer work a little more seamlessly. Before hand that really wasn't happening at all.
It's done by rendering your driver on a completely different driving lane than the one your friends will see you on when they are playing with you. I'm not really exactly sure how that all works, but I'm keen to give Trials Fusion another try. It's been a while and I've got a lot of DLC tracks to play catch up on.