I feel bad for the shmuck who paid that much. These sites aren't an accurate source. Website analytics, monthly income, unique traffic, number of advertisers, post or content quality, unique content, active posters versus non-active and or spam accounts that have been disabled, costs for monthly maintenance, staff salary, etc. All of which are only made available to the owner.
All those factor in to what a site's real worth is. I've bought and sold communities in the past, and this is the proven method for evaluating how much a site is worth, and how much it can be sold for. These sites base themselves on Alexa, PR, and other useless figures when it comes to placing a legitimate value on a site. For fun I entered 3 domains I've had for years but didn't do anything with them and there was no record of any of them being used when I purchased them. They're all valued between 100-20,834.52... As accurate as Helen Keller being a sniper.
Feel free to message me the name of your friend's business and so that I can see if I can sell him three worthless domains and get 2 months worth of paycheck for free.