by AlmostThere » Wed Feb 24, 2010 8:25 pm
The fire rings are ones that people have built while practicing dispersed camping, which is what backpackers do - find a site they like and set up camp. The rangers will encourage you to use the well used sites that everyone else has used before to diminish the wear and tear on the rest of the wilderness, in some of the most well used areas of the park - like Rancheria Falls, or Little Yosemite Valley, or the areas along the JMT. In the areas hit hardest, they will restrict camping to areas the park rangers designate.
You can camp anywhere you like outside the restrictions described on the Yosemite website (distance from roads/trailheads, distance from the water/trail, etc.). I frequently do - but I have a hammock and rarely build a fire. People with tents tend to favor those flat spots every other tent user has camped on, and they also tend not to go far from the trail.