Here's my experience.

I never understood double opt-in. Not from a "this is the email standard, every does it, you're nuts not to do it, what about SPAM complaints, you'll get a better quality list" point of view... That gets pounded into everyone's head enough--so I'm clear on that.

I'm talking about viewing double opt-in from the point of view of my customer. I try to do things that keep them from having to actually WORK to get messages from me.

They already asked once to get my message. Making them ask twice is like asking them if they're really sure they want to buy my widget after they've already said they want it.

I've killed way too many sales by asking questions AFTER the sale was already made.

And until AWeber and everyone else can 100% guarantee that my subscriber is going to get that confirmation email, well, then I KNOW I'm losing money.

I used double opt-in for a while, and in all cases it was a pain. I turned it off. Sales went up.

That was neat.

And if you branch out with your marketing and don't JUST depend on email for every cent your business earns, then it works even better.