Yeah. It's very dependent on the system but in general people would be far more likely to vote for a fringe party as its ni longer a wasted vote.
So it's good for everyone from the Greens and communists to the BNP and ukip. They all get in the game, how many seats depends on the system and the unknown latent support for such groups. All at the expense of the establishment and there us an argument that in big parties like tory and Labour there is better self regulation (debatable, but as an example reform will stand behind any loon with virtually no background checks, much harder to become a Labour candidate).