Do mailing list builders work?

Some data about mailing list builders:

Between November 2017 and October 2018, I participated in 50 different mailing list builders, including ones I ran and others which I paid to join. Those builders to date would have cost me $4020.60 if I had paid for them all. As I mentioned, I ran many of them so it wasn't like I paid for those ones. However, for the purposes of this analysis, I am including those costs as well.

In those builders, I collected a total of 160,848 emails in total.

87,050 were new to me when I got them (some participants then went on and joined multiple, and were then captured in the 160,848 total number). Calculating that out, it ends up being $.02 per lead and $.05 per new lead. Previously, before builders, I paid anywhere from $.33-$1.50 per new lead, so that's a drastic cost reduction.

However, people then wonder how EFFECTIVE those leads were in staying on my list.

With the process I use, no matter what audience I select for a builder, I always filter for readers. S…