The Steam Workshop is coming to Left 4 Dead 2. That'll make it even easier for players to sample user created campaigns, but Valve are planning to take things a bit further and release an "expanded scripting tool" that will let modders create "deeper and more varied experiences inside of Left 4 Dead 2." That includes new rule sets that can be integrated into new campaigns, or traded as custom mutations through the workshop.
"To compliment the new access to maps, weapons, and items, we are also creating an expanded scripting tool to allow deeper and more varied experiences inside of Left 4 Dead 2," say the Left 4 Dead team on the Left 4 Dead 2 blog, though no further details are provided. Perhaps this'll take the form of an auto-update with a community spotlighted mutation of the week, but who knows. It might integrate a Spitter into your lounge for all I can guess. I really hope it doesn't do that.
The news heralds a change in this week's official mutation to a fresh one called Follow the Liter, which will only let survivors salvage a single can at any one time. This ought to focus the action a bit on those scattershot Scavenge mode maps.
Update: Oh yes, these bonus features are planned "also for Linux users as well starting in the middle of next month and rolling out from there." Woot!