The life of many a PC game has been revitalised and extended by player-made mods, but not every developer has the resources and inclination to officially support them. Developer Respawn Entertainment has confirmed that Titanfall won't have official mod support at launch, but it's open to the possibility of sorting that out later.
Asked whether the FPS would support mods or user-made maps, Respawn co-founder Vince Zampella responded "not at launch for sure" on Twitter (via Eurogamer). "Will have to evaluate after launch," he added.
Well, at least that's not a no. Given that the game's built upon Valve's Source engine, which has been heavily modded for--gosh--almost a decade, it seems fairly likely that industrious modders will figure out how to get some things into the game unofficially, at least. Large-scale mods would likely require an official toolkit, though.