We are about to launch a new service that you embed in a website or Facebook.
We consider using the following to get various source of income.
1 - Ad's for free (package one)
2 - Remove ad's for 1 dollar
3 - Subscription with 3 packages based on number of users.
4 - Mass number of users (by email)
1 - first what do you think?
2 - second, do you have any idea what DISQUS business model.
I could not find the way they make money.
But i know they have millions of users.
To address question #1 and your numbered bullets:
Regarding question #2, their focus seems to be to create mass adoption, then sell into big companies with paid services for analytics.