Ask HN: I have a portal with 500k monthly users? How do I monetize it?

The traffic is increasing by almost 7-10% every month and monthly users have crossed 500k. In spite of such high traffic numbers, the revenue from Google Adsense is negligible. I want to get rid of Adsense and want to monetize it via some other means.

What are some possible ways through which I can monetize the site?

Link: http://www.bonobology.com/