The basic points of Habermas' theory of public sphere are as follows. First the public sphere is a place of discourse. It is a place where people can come to speak publicly of their political and social concerns (figuratively speaking). It is in distinction from private sphere and the government, which is called the Sphere of Public Authority. In short, the public sphere is a place where public opinions can be formed
Second, according to Habermas the public sphere is important for any democracy to succeed, because this is where ideas are shaped and formed. Moreover, it is here where the government is able to hear what the opinions of the people really are.
Third, the true test of whether a government is a good one or not, is whether the government listens to the popular opinions of the public sphere.