Champions Online first announced that it was joining the ranks of other games offering a no-subscription option, it included a mention that free members would be locked into archetypes. Archetypes were described in broad strokes as a chance for players to develop along the lines of famous heroes from comics, with a locked progression path but the same basic power level. While the development team hasn't yet expounded on what the precise archetypes will be, it has put together a short description about the differences players can expect between the normal free-form heroes and the coming archetype heroes.
As it turns out, archetypes will end up with slightly fewer overall powers than freeform heroes but with the same general power level. The preview explains the split as being one of versatility -- freeform heroes will be able to take many roles, but archetype heroes will perform one role well and that's it. If you're one of the players looking forward to trying Champions Online as free-to-play, or if you're just interested in the new build system, take a look at the full rundown and keep your eyes peeled for the coming details on the archetypes themselves.