I once worked for a very successful small firm whose primary product was a weekly email / newsletter: subscriptions start at around £20,000 / year. Their produ

I once worked for a very successful small firm whose primary product was a weekly email / newsletter: subscriptions start at around £20,000 / year. Their product was analysis (energy markets), their customers were the banks / hedge funds, etc. The analysis was provided by, um, analysts. These guys (and women) were Phd's, they were extremely well qualified and experienced. Anyway you don't have to be a phd: the point is that if you have knowledge / expertise there may well be people who are willing to pay for it - the medium doesn't really matter.