Every time I create a lens, I always add an optin list to it. At the time of writing this I have over 75 lists, some have a few hundred members, some have less than 100. I know that I am going to continue growing those lists and because I only send out quality information I know that my lists are much more likely to purchase something from me.
By using aweber, I can create unlimited lists and manage them all from the same dashboard. I can also load up my auto responder for weeks in advance. Some of my lists get an email from me once a week for the first 5 months of joining.
Only one of those emails is asking them to purchase something, the rest is quality information.