Peak Bagging Etiquette, Courtesy, and Common Sense

I know the following information is old hat to the majority of the outdoor enthusiasts out there plying the peaks of the lower 48, but for those who are new, clueless, or just plain rude, please consider the following:

From R.J. Secor in The High Sierra Peaks, Passes, and Trails on ducks and cairns:: "These markers appear regularly along High Sierra routes. Ducks are also known as cairns; a duck is a small cairn erected by well-meaning hikers to show the correct route. The problem with ducks is that they seldom actually show the easiest route. They also have a tendency to direct all cross-country hikers onto the same path. This leads to the creation of a use trail, which usually scars the land above timberline. There are many use trails in the High Sierra but we must do everything we can to prevent more from being created. I believe that anyone who leaves the trail and sets out cross-country should be capable of finding the correct route on his or her own without the assistance of ducks. Don't build ducks, and destroy all ducks encountered."
This is an example of what you will generally find passing as a duck, an ungainly pile of rocks. 99% of the trail markers I have seen in the Sierra are unnecessary, and some of them are comical in their placement. If you decide it is absolutely necessary to build a duck, build a good-looking one.
For the most part I agree with R.J., but occasionally there are marker placements that show devious entries into chutes or onto hidden ledges that are actually valuable. These should be left in place, but for ordinary cross-country travel, ducks or markers are unnecessary.
This is an example of a cairn. I have seen cairns used as trail markers many times, but traditionally cairns are built on summits, sometimes to house the summit register, or as memorials to fallen comrades. Sometimes you will see a memorial cairn at the base of a peak Either way, let's try to maintain the tradition.
Peak Bagging Etiquette & Courtesy
 
If traveling on a maintained or use trail, don't cut the switchbacks. Have fun, and push yourself  
Uphill hikers have the right of way Don't build ducks or trail markers  
If camping at the trailhead, in an established campsite or not, be courteous and quiet, some turn in early for an early start Don't gobble up all of the space in the summit registers, keep your comments short and succinct, and leave the registers in place  
Be friendly Don't trundle  
While traveling along the trail, please don't be overly noisy Leave your dogs at home  

And lastly, this suggestion from my good friend Joe Macaluso, No Posing. Obviously I can't endorse this one myself, as Scotty and I posed all summer.