This is a topic near and dear to my heart.

We have yellow lines on our paths. While it probably helps somewhat, you're still going to get "trail hogs." There are people who insist on walking/running two or three abreast, usually yapping away and can't hear you when you warn them that you are passing on the left. We also have the same stoller obstacles, and regardless of the line dividing the trail, I've seen two double-wide stollers walking side by side and refusing to yeild.

The worst are the IPOD wearers because most of them can't hear you.

I always warn folks that I'm passing on the left and I thank them as I go by. I've found that being very polite works best. I tell people who refuse to yeild that I can't see around them and that I'm going to have to stay behind them until I can safely pass. Sometimes, they are just oblivious and will move over. Then again, I've encountered hostile folks (weirdly enough, most are females) who refuse to move to the right. I just try to remember to do like Mr. T and "pity the fools," not get upset, and just figure that they are helping me build my biking skills by providing "challenges." haha.

One thing to keep in mind is speed. I don't believe in hammering on shared use trails unless I have a long stretch of clear pavement. If I'm coming up on someone and I'm going fast, I usually tell them, "passing on your left and I'm coming fast." I've encountered countless rude cyclists who, no doubt, have made others using the trails less friendly to cyclists in general