It is indeed interesting to watch that the pirates did already have quite a notable effect on german politic after they won seats in Berlin last year. The position of the leading party (CDU) on things like ACTA didnt change 100%, but you could see many of the politicians changing their arguments pretty quickly after that first election.
And this is not the first time this has happened. The green party which sometimes got up to 25% in nationwide polls and was in the government for some years, did have that same effect on the two big parties. Without the green party it would not be so "mainstream" today for all parties to be very close to each other on ecology politics.