Letters to Editor

I've been thinking I need to get back into writing letters to the editor. Partly to vent, partly because I feel like I should be doing or saying something, and partly because I hope it might make some small difference. But I'm pausing to think a bit first. What makes a good topic? What makes a good letter? Who am I trying to reach? Is it worth it? (for a good article that helps make me feel it is worth it, see this piece by Howard Zinn)

For me, what makes me think or has the possibility to change my mind when I read a letter is a good strong case, backed up by knowledge. I am not likely to change my mind when I read a piece that is totally opinion. Maybe that is the scientist in me. On the other hand, a letter of facts is a boring read, and I think people may not even finish it.

Also, what topics do you think are most pertinent right now? What tends to draw your attention on the letters page? Something new? Something kind of "out there"? A short piece versus a long one?

Thanks for any thoughts or ideas.