One per niche.
I am making money out of it, at least 8-10 conversions a week.
This is the spread of my tweets:
I am delivering content - no affiliate links-
I am directing them to my hubs/lens/articles - Affiliate links in some of them-
I direct them to my blog/media site - CPA/Affiliates links in these
See some of my hubs. I have written something about this topic