It is about investing in stocks but with a venture capital mindset (my background is in tech and vc)
For me the audience seems to come in waves because right now I work full time and I haven't focused on marketing much.
but here is what has worked for me so far:
1) write high quality content (i think it's better to write fewer articles but more high quality). This is your best marketing.
2) To start off, tell your family, friends, and co-workers about it - I find them to be supportive and will sign up if you ask, but frankly only the ones interested in the subject matter will actually regularly read the emails. That said, they will give you real feedback.
3) Interest based groups like fb groups can help sometimes
4) twitter - when i participate in the conversation regularly, this can help a lot actually.
5) Rmr what I said about high quality content - Some people actually contacted me about my SS and wanted to talk on the phone/zoom etc. They usually shared the site with their friends/audience after our conversation. One linked me from their blog which drove a lot of traffic. I think this is a great way if you can make it happen.
Overall, I find I have a good sign up rate from folks interested in investing + innovation, and people interested in investing with options.
If you're interested, check it out:
http://playingfordoubles.substack.com/
Anyway good luck!