Are they serious or jokers?

Are guys like the one in the site I found serious and does it work? http://beam.to/dinga2

umm.mm i think it looks like a scam it might be real tho...-->

I didn't look much into the site, but if they are like any other auction based website, they just sell info on the auctions, so you can do searches and see what will be sold at what auctions, you need a membership of some sort to get into most auctions...and then at the auctions, you don't get to testdrive the cars, so it can be a hit or a miss.
Yes there can be some amazing deals...but nowhere near all of them are as good as advertised.

But like I said, I didn't look into the site too much, so I don't know if you were asking about the site specifically or car auctions in general.

they look fake. if you remove the /dinga2 from the address, it is a funky site. If it was legit, I would think they could afford there own website address.