If you haven't seen it, this future-oriented piece by Cato's John Samples concerning the regulation of blogs by the FEC under our campaign laws is prescient and clever. The Supreme Court steadily has narrowed the first amendment's free expression protection in favor of regulation of political speech. The McConnell v. FEC decision was just the most recent step.
If anyone thinks that "bloggers" will remain beyond Congress' campaign finance speech regulation just because they invoke "the Internet", they are probably kidding themselves. And in the digital age, what's the difference between a "blogger" and a "broadcaster" for purposes of the potential to influence the outcome of an election--the concern of the campaign finance laws?
Of course, if Congress (or the FEC) ultimately goes after the bloggers, that doesn't necessarily mean the Supreme Court would go along. But before you bet your house on it, reread McConnnell, where the balance tips much more heavily in the direction of protecting politicians from criticism than in protecting the right of citizens to speak freely.