Here's a resource for small and large "L" libertarians. Libertarian Reddit.
They've got around a thousand other sub-categories at Reddit, most of which help the best o' the Web to bubble to the top.
No account is necessary to use Reddit, but you'll need one to vote links up or down, or to comment. If you set up an account, you can then select which topic's most popular articles appear on your front page when you sign in.
For bloggers....if you ever write something that makes it to Reddit's main page, you'll be very, very happy.