We all know that measuring our email marketing efforts is important.

Of course it is; measurement supports our use of resources, and helps us make changes so we get better results in the future.

But there are a lot of things you could be measuring, including open rate, click-through rate, bounce rate, list size, unsubscribes, and shares.

What metric should your business or organization focus on? We asked that question recently on our Facebook Page, and here’s what you told us are the most important email metrics.

The no. 1 metric that is most important to our Facebook fan participants is open rate (57%), followed by click-through rate (28%). It was surprising to see list size only coming in at 2%, but then again, what’s the point of a big list if no one is opening your messages?

Another interesting result came in from Facebook fan Albert Kaufman, who said feedback/responses was his most important metric: “Responses are probably most important to me. I get a lot of feedback after each of my monthly email newsletters goes out. That is the most important feedback for me as it is often full of reaction, introductions to new people, reminders of things already in motion that I’m writing about, and surprises.”

For a different opinion, Martin Lieberman and Dave Charest, Constant Contact’s managing editor and senior content developer, recently weighed in about what they think are the most important email metrics for small businesses and nonprofits. Click here to read their thoughts.

Do you agree with our Facebook fans that open rate is the most important email metric? What email metric(s) are most important for you? Share your thoughts with us in the comments below.