At the end of a blog entry recounting angry letters to the editor in response to a couple of sentences in a recent column praising homeschooling and private schools, Rod Dreher explained why only the angry letters showed up in the paper:

Dallas readers will wonder why the paper only published negative responses to my column, and will perhaps see media bias in the letters selection. Not true. I work in this same department, and let me tell you, all the people who liked the column and took the trouble to write wrote me personally. The ones who hated it wrote letters to the editor -- which is why they got printed.

So if you like something you read in the paper, by all means let the writer know, but cc the letters column, and let everyone else know, too.