That is the problem with the rights, farm, environemt list I use. Because property rights are so tied into the environmental movement and agriculture I included all three for my list but the number of posts and pings was getting to be too much as you have seen in my freepmail. I have had to cut back and be a little more discriminating.
You know your ping list is too broad when people start dropping out in large numbers. I seriously try not to be obnoxious about pings. Originally, I thought I "knew" who should be on my list, but I made mistakes, and I learned not to make those decisions for people. For the last 2 or 3 years, I only add people who specifically request to be included. And even then, I check out their postings to be sure they're right for the list. I guess I take this stuff too seriously.