Ok, my opinions on a quick glance:
Don't pay any attention to Alexa or Compete scores. Compete's traffic stats are always way off and Alexa rank can be gamed quite easily. Yahoo links are also pretty worthless as anyone can submit their site to 10,000 crap directories and get that number up.
Use something like Open Site Explorer to get a good list of links that are actually worth something. For example, OSE has 132 links for the first file host site you listed which Flippa says has over 10k links from Yahoo. It also only shows back links from 20 different domains.
Plus, the guy didn't even provide verified Google Analytics stats. There is simply no reason not to throw GA on your site for even a week and post verified stats on Flippa. That looks pretty bad.
Look at the Alexa graph for the first file hosting site:
http://www.alexa.com/siteinfo/filebling.com#
See how it's daily reach goes from 0, jumps up to nearly .02 in 2 weeks then declines. That's faked Alexa stats. And let's not even mention that 0 Page Rank sticking out.
As for the 2nd file hosting site, same as what I just said for the first one.
Honestly file hosting sites are the new "arcade sites" which at one point were the new "directory sites" which were at one point the new "humor sites". 99% of the time they are crap sites thrown up on an older domain with some cheap, off the shelf script. It takes these guys a day to put the site up, fake the Alexa rank up and even buy some cheap, crap traffic to boost the Google Analytics stats. Add some Photoshopped income screen shots and wait for a sucker with cash to show up.
And holy crap, just look at that last site, Lolsnaps.com. Look at it's Alexa chart, see that's got a PR 0 and that Open Site Explorer has a whole 9 back links for it and ask yourself if you think that site is getting 2,000,000 uniques a month and earning $18k a month.
I mean, it's Alexa rank jumped 296000% in 3 months. Yeah, ok. But hey, he's got verified analtyics stats. Lets look at them. Wow, the majority of traffic is coming from FaceBook, here's what the seller has to say about that when questioned:
I've integrated facebook widgets into my site Specifically 'Share' and 'Like' buttons under every picture.. Test out the like button and see the news feed story that it creates on your wall. People love clicking these... The more likes the more traffic.
I don't even have a stumble upon button and take a look at how much consistent traffic i get from them daily, now the new owner will have to get the same effect going with digg. and also SEO and other sources i don't know about.
I add content every morning when i wake up anything from 5-10 items. In the admin you can choose if you'd like the content to be active or un-active. If there is any un-active content in the admin section every 8 hours it selects a random amount of un-active content and activates it. There is also a count down timer on the page which displays when more content will be added.
I have a $240 dedicated server with a 100mb/s uncapped line. I have a guy who manages my server and he charges me $100 per month.
I have about 15 sites i check daily for content, i also have an upload section on the site and i get about 20-40 new items daily from users.
Dude anything is possible if you using the right social plug-ins and your site isn't cluttered and if you have good content.
Wow, who knew you could take a new site and jump it to 2,000,000 uniques in a month just by adding 5-10 posts a day and adding Face Book "like" buttons on every page. Yeah, that explains it. Oh, wait, it must be the countdown timer.
