Plenty of rumours about this going on in the past. I just found a way to more the less calculate this. Might be interesting.
Summitpost is currently the 51,752 biggest website in the world. The domain receives about 7,604 unique visitors and 43,343 (5.7 per visitor) page views per day. Based on this information, you can estimate that it earns about $23 USD per day and gives the site an overall value of $16,653 USD.