question about non-confirmed subscriptions

Good advice but I would have worded this:

to:

But that's just me. Unless they have enough faith to take the plunge and opt-in, they'll never know if it works or not.

OP, keep in mind that your opt in page and your lead magnet (the freebie) are steps in a process, not a singular event.

Something led them to your opt in page. What they find should be congruent with what brought them there. The offer should be congruent with the visitor's intent. The page they see after opting in should flow, as should the confirmation email, the success page and the thank you page and email. Each piece should be like a link in a chain.

One thing I often do differently, especially in niches outside of IM/MMO, is position the confirmation process as something I do as a favor to the subscriber. Rather than planting ideas about spam, I simply say it's a test to make sure my server can deliver successfully to their inbox, and clicking the link just confirms that the test message reaches the right place. Add the bit about the junk folder and whitelisting, and you're set.

The approach is based on reciprocity and consistency.

I'm offering a valuable freebie in return for the email, and I'm simply asking them to do me a favor and click the test link. Once they do, they've done me one small favor, so to be consistent, the next time I ask for a small favor, like clicking a link, they do so.

Do it right, and you build an image in their heads as someone who opens your emails and clicks your links, etc. When you ask for another favor (buy something that's in their best interest), they do.

If you're using a service like Aweber, where you get charged by list size, you might want to periodically purge unconfirmed addresses to lower your bill.