I plan to gradually create several landing pages, each of which I will dedicate to a separate topic. Then I will dedicate a separate campaign to each of these pages. Thanks for the tip with good topics.

It's too bad we don't have a way to track whether any of these clicks actually turned into memberships

This is the biggest problem. Without it, it is impossible to assess the true effectiveness of what I do. Still, I think reminding people of Steem's existence is worthwhile, at least maybe I'll encourage them to do some further independent research.