Making the list of the top climbing blogs on the Internet were sites such as Climberism and PlanetMountain, both of which I enjoy reading regularly. But Outside's top pick in this category is one that I whole heartedly agree with, as Climbing Narc is always a great read to keep up with what is happening in the climbing scene.
The top 10 running blogs is filled with plenty of great options as well, and if you're not already a runner, reading these sites will probably motivate you to start. I've always been partial to iRunFar and enjoy reading Peak Performance as well, as both offer plenty of inspiration for my own running. The top blog on this list is Science of Sport, which is a new one to add to my daily web activities.
Finally, we have the top 10 fitness blogs, which includes Runblogger, which is curiously listed here and not under the running blogs, and Sweat Science, which is always a good read when you're looking for the latest news and analysis on fitness trends. The New York Times Well Blog tops the list in this category thanks to its excellent writing, breadth of topics, and practical advice.
Between all of these lists, you should find at least a few new bookmarks to add to your browser of choice. There really are some excellent blogs listed amongst the 70 websites that Outside has recommended across all of these lists. They'll definitely keep you informed on what ever topic they focus on.