In light of I.F. Stone's book on the trial of Socrates, it seems clear to me that Socrates' aim in the Apology was to cast aspersions on the freedoms of Athenian democracy by getting himself convicted. Socrates was pro-Spartan and anti-Athenian, and thus held no love for the judicial process he had been called to participate in. He knew all too well that his followers had been involved in recent tyrannical conspiracies, but he also knew that the Athenians were fond freedom of speech and were uneasy to convict him merely for stirring up trouble. Since he was in his 70s and hadn't much longer to live, he used anti-rhetoric to force them to convict against their own principles. For example, his reference to Chaerephon (p. 152) is really meant to remind the Athenians of his anti-democratic sympathies.
His followers, of course, aimed to bolster their leader's position and Plato in particular wanted the charges against him to look excessively vague.