...

I wasn't using one and I think it hurt me for my other pen names.  We'll see if adding one now helps turn things around or not.  But with those other pen names I can see people read through all the stories by that name and then my new releases are dead in the water, which makes me think that people would buy those stories if they knew they existed.  Of course, I had someone read through a whole pen name yesterday but not sign up for the mailing list, so...

(And as an aside related to a different thread, I am completely guilty of the overuse of so.  Chalk it up to my years in California.)

I didn't have one until June. Now I do; growing but still small (about 1100 subscribers). I have very good open & click-through rates (about 65% and 20%, respectively--as high as 80% and 40% when I have a new release). I'm not sure it's been that gigantic for me, actually--not having one, or having one. But as everybody says how important it is, now I have one.

I think if you engage with your readers on social media then perhaps a mailing list isn't so important, as you can announce new releases etc. that way. But I don't do Facebook or any of that stuff so for me it's pretty vital.

I think you're right. Facebook is big for me.

I'd already sold close to 70,000 books before I implemented a mailing list.
I look at it like I lost a lot of possible subscribers and future sales.

I believe the argument in favour of a mailing list over social media interaction is that you own that list. If FB decided to change the rules tomorrow, you could lose contact with thousands of readers in one fell swoop. With a mailing list, those names and addresses are yours forever.

I'm not. I probably should be, but I have an unfortunate tendency to assume everyone's on Twitter. I also can't face editing sign-up links into my existing books and re-upping them at the moment. I'll probably get around to it eventually.