Andrew Perrin, assistant professor of sociology at UNC, is studying newspaper letters to the editor. So my ears perked when he spoke Sunday at a journalists' roundtable.

Perrin didn't want to give away his findings just yet. But he did say a comparison of people who wrote letters and seven-day a week subscribers who did not write letters found the two groups to be "remakably similar."

Based on that, he said, letters provide a "reasonably good pulse of what people are thinking." (No mention of bloggers.)

Perrin did offer writers this bit of advice: stick to one topic. Too many writers take on too much, then probably get disappointed when their missives are edited down. The mean number of topics in the letters he studied was nine. The most topics in a single letter: 36!