A Makaque monkey over on Twitter told me about a great article at Get Elastic on how a retailer tested two versions of their email to see what worked better:

Which version do you think got more clicks and 15% more sales?

Want to run tests with your own emails? It’s free in MailChimp, and it’s unbelievably easy and automatic.  Even a little fun. And people who use it get better results than people who don’t. It’s called A/B testing, and here’s how it works.

I recently blogged about some interesting A/B Split data that I’ve been sifting through for a report we’re working on.

Thought I’d post another interesting observation from a handful of campaigns that ran A/B Split Tests on their subject lines (company names disguised as “Acme”). The first 4 are from the same company, sending emails for 4 different web properties that they run…

In almost all the examples above, the subject line with “free” had a lower open rate. So should you avoid the word “FREE” in your subject line? In my opinion, don’t use “free” if it detracts from relevance. If you replace your company name with “free” or if you remove the urgency with “free,” your open rate is going to suffer.